Re: [Qgis-user] wishing for accurate lattitude/longitude from, a cell phone

[Michael . Dodd]

Coming back to the reference I mentioned much earlier in the string, one of the 
graphs is shown here: 
https://besjournals.onlinelibrary.wiley.com/action/downloadSupplement?doi=10.%2Fj.2041-210X.2011.00118.x=MEE3_118_sm_FigS2.doc

It shows the typical variation in location indicated by consumer gps units over 
time and how you may be able to get a better location by averaging over a 
longer period BUT that this location is still likely not to be the 'correct' 
location.

The particular graph shown here it is part of a 5 hour run with several 
consumer grade gps units and set of smartphones (only a small set of the data 
shown in that graph), the smartphones tested had some kind of averaging built 
in as they slowly got to within 1-2metres of the 'correct' location after about 
2 hours and stayed approximately there for the remains of the 5 hour run.

What I did not try is what would happen if you did the 2hours of averaging on 
several separate days, presumably on the archaeological fieldwork there might 
be the chance to do several days of 2 hour runs and with these averaged as well 
then half metre or even better might be possible but is not guaranteed.

One separate bit of information that could be of use for archaeological 
fieldwork is that besides the survey grade Leica dgps we also used 0.5m 
accuracy kit (the same leica kit but just using Egnos instead of Smartnet) to 
find buried markers for total station surveys. You would think that 0.5m 
accuracy plus a metal detector should be able to find the metal survey pin but 
it often took a very long time in rough grassland habitats so definitely having 
a way to get more accurate than 0.5m is better even if it is only to find the 
buried origin marks for total station. By comparision when full differential 
gps is switched on you walk exactly to the buried pin with no deviation and hit 
immediately.

From: Qgis-user  on behalf of QGIS.USER 

Sent: 27 May 2020 16:19
To: 'Garth Fletcher' ; qgis-user@lists.osgeo.org 

Subject: Re: [Qgis-user] wishing for accurate lattitude/longitude from, a cell 
phone

CAUTION: This mail comes from outside the University. Please consider this 
before opening attachments, clicking links, or acting on the content.

Hi Garth,
Thank you for the correction and the additional information. Much 
appreciated.

My current thinking is that in the archaeology we do, the intra-site (relative) 
measurements are quite good but what is inaccurate is the absolute 
measurements. We can set out our grids with cm accuracy but can only locate 
them on the ground with 10s of metre accuracy. It would be good to have a low 
cost way of establishing the absolute position even if that took time and/or 
was off-line.

Ray Carpenter,
Chapel Archaeology

-Original Message-
From: Garth Fletcher [mailto:ga...@jacqcad.com]
Sent: 27 May 2020 15:25
To: QGIS.USER; qgis-user@lists.osgeo.org
Subject: Re: [Qgis-user] wishing for accurate lattitude/longitude from, a cell 
phone

Hi Ray,

Apologies for the typo - I had typed iGS3, but iG3s is the right number.

iGage http://www.igage.com>> iG3s, now replaced by the iG4 which 
adds Galileo
tracking but otherwise seems very similar to the iG3s. $2400 US.

These track satellites from the US GPS, Russian GLONASS, Chinese BeiDou
and, with the iG4, European Galileo constellations.

Their sole function is to record from all the satellites they can track.

They produce a RINEX format file which can be sent to a post processing
service such as Canada's Geodetic Surveys' CSRS-PPP:


The longer the observation (recording) duration, the better CSRS-PPP can
converge to an accurate location.  In my experience in New Hampshire's
heavily wooded environment, a 30 to 45 minute observation time generally
gets me to better than ± 1 meter accuracy.  Yesterday a 6 hour long
observation in a small field surrounded by forest converged to within 1
inch.  Dense forest canopy reduces the number of satellites that can be
tracked. Also, some times of day are better than others in terms of the
number of satellites and their geometry, see:
   

The iG3s was perfect for my specific conditions, but I think it is not
optimal where many locations within a site must be accurately measured
** relative ** to each other.

Such sites would be better served by differential measuring where two
receivers are used.  One is the "Base" which is kept in a fixed location
while the other is the "Rover" which is moved from place to place.

The Base constantly transmits its data to the Rover over a RF link.  As
long as both are fairly close (within a few kilometers of each other),
both see essentially identical satellite errors which can be cancelled
out to produce a very precise ** difference ** in location between Base
and Rover.

Note that the absolute accuracy of their positions may not be as 

Re: [Qgis-user] wishing for accurate lattitude/longitude from a cell phone

[Michael . Dodd]

One app that claims to do a lot of what high precions gps does is 
https://play.google.com/store/apps/details?id=gr.stasta.mobiletopographer=en_GB
 It does allow averaging and shows quite a lot of what is going on, but still 
limited by the phone's antenna.  May have to take some of the accuracy figures 
it produces with a pinch of salt and remember that graph I mentioned earlier in 
this thread that shows how the errors change (direction/size) over time during 
the day.
[https://lh3.googleusercontent.com/KQTZIANk_20sZNVWJWTLQs0haOnA4hAXmLcPSwU_Adb4TPCt_jC5RowT1moahou2Jq4]
Mobile Topographer Free – Apps on Google 
Play
Your mobile Topographer! The leading tool for the professional surveyor or 
anyone who wants to mark his property, offering the best accuracy and extensive 
functionality that no other app can! *** Increase GPS accuracy using: - 
Weighted averaging (on every axis). - Map calibration. - Device calibration on 
map, or on a know point. *** Display and convert GPS geodetic to Cartesian EN 
coordinates ...
play.google.com


From: Qgis-user  on behalf of 
j.hu...@post-ist-da.de 
Sent: 23 May 2020 20:35
To: qgis-user@lists.osgeo.org 
Subject: Re: [Qgis-user] wishing for accurate lattitude/longitude from a cell 
phone


CAUTION: This mail comes from outside the University. Please consider this 
before opening attachments, clicking links, or acting on the content.

Hi Steve,

I think there are two different aspects to your question:
1) Accuracy of GPS Devices
I agree with others that you can't expect a better accuracy than the 10 to 30 
feet you observed with a smartphone or a simple handheld GPS. This might 
improve by averaging, but this takes time. Survey grade GPS devices are very 
expensive. It is possible to get good modules and antennas as components, but 
building a complete GNSS system requires time and skill. This would reduce 
cost, but only to several hundred instead of several thousand dollars, so this 
is no option in your case. Besides, you will still need a correction data 
service (usually costly) or use two receivers (rover and base).
So you probably have to stick with your phone, which is more flexible regarding 
the software than a handheld GPS.

2) Software
The accuracy of the recorded position should not depend on where you tap the 
screen - a good app should allow to record the current GPS position. I am using 
Locus Map (Asamm Software) for a while now, it works quite well, although it 
does not allow position averaging. There is a free version, you could try that 
first.

Regards,
Jochen

Am 22.05.20 um 20:54 schrieb Stephen Sacks:

In order to make widely available some wise advice, I'm sending to this list a 
message I received from Neil B.  In addition to Neil's message below, I want to 
mention that Nicolas Cadieux also provided similar information, saying I'd have 
to pay around $1,000 for equipment that gives consistently accurate location 
coordinates.  And thanks, also to Falk Huettmann and Bernd Vogelgesang for 
their replies.

Message from Neil B:

Hello Stephen.
Glad that you're having success. I would like to start off by saying that it is 
best to always reply to the mailing list and not directly to the person who 
submitted the email. Mailing lists work really well in that there is a pool of 
people out there who may be able to offer advice or may have an alternate 
method to solve the problem that may turn out to be a better way. On the flip 
side by maintaining the email chain through the mailing list, the follow up 
emails that provide information are stored in the archives which benefits 
anyone searching the internet to have the complete trail of information.

As far as your results they are acceptable for the device you're using. GPS in 
phones are never built to precision survey standards and there is no reason for 
them to be. If you're within 30ft of where the phone thinks you should be then 
you can easily navigate the rest of the way by visual sight. High end equipment 
to achieve sub-inch accuracy is probably in the range of thousands of dollars. 
One thing to keep in mind is there is a difference between the accuracy of a 
device and to what level of precision they display. While the app on the phone 
may display 8 decimal places of a lat/long coordinate and tell you if you have 
moved a foot, it doesn't help that the coordinate it is displaying is out +/- 
30 feet. The accuracy of a device can also be affected by the environment where 
the device is being operated. In regards to cell phones, they use multiple 
sources to determine location such as GPS, cell phone towers, and wifi points 
to perform the triangulation. Lack of line of sight to satellites, signals from 
cell towers bouncing off of surrounding buildings, or someone's wireless router 
using 

Re: [Qgis-user] wishing for accurate lattitude/longitude from a cell phone

[Michael . Dodd]

https://besjournals.onlinelibrary.wiley.com/doi/full/10./j.2041-210X.2011.00118.x
 I did this quite a few years ago but in the graph in supplimentary material it 
shows how the accuracy of one consumer grade gps varies over time (at a fixed 
point). At the time I also did a lot more measurements using mobile phones and 
consumer grade units on a grid of points in the field, that was not published 
but basically the phones were often as good as if not better than the consumer 
grade gps units especially when using certain apps to average points.
[https://besjournals.onlinelibrary.wiley.com/cms/asset/1c8a8949-7fe4-48ea-beb9-01d4efee7ddf/mee3.2011.2.issue-6.cover.gif]
Where are my quadrats? Positional accuracy in fieldwork - Dodd - 2011 - Methods 
in Ecology and Evolution - Wiley Online 
Library
Introduction. There has been much written about sampling design, spatial scale 
and the need for permanent plots in ecological long‐term monitoring, for 
example, the paper on spatial scaling in ecology has been cited over 1500 
times, but one frequently ignored issue, intimately associated with sampling 
design, scale and permanence of plots, is how to locate positions accurately.
besjournals.onlinelibrary.wiley.com


From: Qgis-user  on behalf of Nicolas 
Cadieux 
Sent: 23 May 2020 16:34
To: Randal Hale 
Cc: qgis-user@lists.osgeo.org 
Subject: Re: [Qgis-user] wishing for accurate lattitude/longitude from a cell 
phone

CAUTION: This mail comes from outside the University. Please consider this 
before opening attachments, clicking links, or acting on the content.

Hi,

This is a very interesting list. It basically confirms what I thought. Consumer 
Point and shoot deceives are all around 2-6m with no canopy. The average 
multiple positions basically give you a better idea as a gps may get lucky.  It 
would be nice to have the full methodology for this and more data (like the 
number of satellite and the position of the constellation and the gps price 
list) but it’s very interesting none the less.  I was also happy that the data 
confirms the precision of the gps Sx-Blue 11. This claims to be sub meter and 
my tests indicated that on our office unit but it’s nice to see it done 
elsewhere.  For about 2000$, this gps is pretty good. As for the rest, the 
difference between 150$ and 1000$ is probably  more a function of the options 
(like maps and screen size...) and not a question of precision. It would be 
nice to know what gps chips they are running...

Interesting thing also is that based on my reviewing the data on my phone 
(without graph or cross tabulation tables) is that the Glonas Constellation 
does not seem to help much.  Quick stats on this list would confirm this. Maybe 
this is just a figment of my imagination because there’s only so much 
information you can grad without running proper stats.

Thanks for the post.

Nicolas Cadieux
Ça va bien aller!

> Le 23 mai 2020 à 09:02, Randal Hale  a écrit 
> :
>
> One other thing that may or may not be of use but the USDA Forest Service 
> Publishes a GPS Receiver Report that covers phones - and that's helped if 
> I've had a client go "Well I have a Apple  or a Android ". 
> At least I feel slightly better going "good enough" or "no not good enough".
>
> It should be good worldwide (but I will admit I think phones are my 'tech 
> ceiling' these days) but your mileage may vary.
>
> https://www.fs.fed.us/database/gps/mtdcrept/accuracy/index.htm
>
> Randy
>
>> On 5/22/20 8:55 PM, Priv.-Doz. Dr. Maria Shinoto wrote:
>> Somehow I did not follow the discussion, but like to add some of our 
>> experience.
>>
>> We are doing field work in a remote region in the southern Japanese 
>> mountains, archaeological surveys on the ground based on LiDAR data.
>>
>> A simple Garmin etrex10 is mostly reliable in an area of 40cm by 40cm around 
>> a measured point, if used repeatedly at this point and the point is located 
>> in the middle of a valley. Even cell phones do a good enough job. As soon as 
>> we get closer to the steep slopes, the accuracy of the Garmin is less than 5 
>> to 10 meters. We can check this with the detailed LiDAR based map, and 
>> geologists told us, that even an expensive device could not be more precise 
>> under these conditions. So we decided to measure traditionally on the ground 
>> if precise measure is necessary, otherwise note the GPS data and the 
>> location as shown in the map.
>>
>> To sum up, we came to the conclusion not to spend money on an expensive GPS 
>> that may not work in the shadow of steep slopes -- or in the streets of New 
>> York. -- I appreciate any additional advice, and hope that this experience 
>> can save Steve's organisation some money...
>>
>> Best,
>> Maria
>>
>>
>>
 Am 23.05.2020 um 03:54 schrieb Stephen 

Re: [Qgis-user] Problem with upgrade to QGIS 3.12.1

[Michael . Dodd]

It has been discussed on the list several times and 
https://github.com/qgis/QGIS/issues/34983 there is a ticket but does not seem 
any progress in fixing it.
[https://avatars0.githubusercontent.com/u/483444?s=400=4]
QGIS "Ballpark Transformations" · Issue #34983 · qgis/QGIS · 
GitHub
So for me (english speaking guy in the southern United States) I use the term 
"ballpark" when I need a very loose fitting answer. As in "How much to fix this 
car - can you give me a ballpark estimate" and 'ballpark' is know to be 
imprecise.
github.com


From: Qgis-user  on behalf of QGIS.USER 

Sent: 31 March 2020 16:34
To: qgis-user@lists.osgeo.org 
Subject: [Qgis-user] Problem with upgrade to QGIS 3.12.1

CAUTION: This mail comes from outside the University. Please consider this 
before opening attachments, clicking links, or acting on the content.

Hi All,

OS Win 7 & Win10.

UK based and always use UK CRS EPSG:27700 (OSGB 1936/ British National Grid) so 
I have an enhanced conversion utility (OSTN15_NTv2_OSGBtoETRS.gsb) installed in 
my QGIS profile.

After upgrading 3.12.1, I get an error message that I need to install 
OSTN15_NTv2_OSGBtoETRS.gsb (despite it already being in my profile). Attempting 
to install it (via the warning) results in an error message about unable to 
access the relevant folder in my profile. I can solve that problem by deleting 
the existing copy of OSTN15_NTv2_OSGBtoETRS.gsb in my profile and it will then 
install correctly. However, even then I still get a warning that the best 
conversion is not available. Reverting to 3.12.0 solves the problem So for the 
moment, I am staying with that version.

Is this a known issue please?

Stay Safe,
Ray Carpenter.



___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] Question On "BallPark Transform"

[Michael . Dodd]

Is there any more news on this 'bug' as it appears to be serious or it might 
simply be the wording.

Example:
Project created in old version of qgis and opened in recent version. It comes 
up with the message about "Ballpark Transformations" and suggests installing 
proj-datumgrid-europe-1.5.zip to enable a better transformatoin between 
epsg:27700 and epsg:4326. The project contains the OS GB1936 system and WGS84.

So I installed the relevant .gsb files in the correct directory with the other 
.gsb files, restarted and tried again to open the project.  This time it did 
not come up with the message suggesting the download but instead just suggested 
using one of the other transformations which are less accurate than the proper 
OSTN15_NTv2 transformation.

Need to know why it is doing the less accurate transformation and how to get it 
to do the correct transformation instead.

From: Qgis-user  on behalf of Randal Hale 

Sent: 27 February 2020 17:56
To: qgis-user@lists.osgeo.org 
Subject: [Qgis-user] Question On "BallPark Transform"


CAUTION: This mail comes from outside the University. Please consider this 
before opening attachments, clicking links, or acting on the content.

Greetings,

I received an email from two users with 3.12 asking about "Ballpark 
Transformations" - the exact phrase was "Used a Ballpark transformation from 
EPSG:4326 to EPSG: 2274".

I've been able to generate the message twice by:

  *   changing the projection of a new project with no data from 4326 to 2274
  *   adding data with an incorrect spatial extent that I believe was in 4326 
and applied to a project in 2274 (I think - I currently don't have access to 
that data to confirm)

I've found mention of it here: 
https://qgis.org/api/classQgsCoordinateTransform.html#a16adb051fafc25058c0040a310f1606b
  


The expanded message in QGIS is:

An alternative, ballpark-only transform was used when transforming coordinates 
between EPSG:4326 - WGS 84 and EPSG:2274 - NAD83 / Tennessee (ftUS). The 
results may not match those obtained by using the preferred operation:

Possibly an incorrect choice of operation was made for transformations between 
these reference systems. Check the Project Properties and ensure that the 
selected transform operations are applicable over the whole extent of the 
current project.

If I check the project properties there is no Datum Transformation defined 
after all this happens.

I'm assuming that if a project has no data and one jumps datums by changing the 
projection it's saying "Hey since there is no data this transformation is a 
"ballpark" i.e. not exact". Is there a preferred way to dealing with this after 
it happens?

Randy

--
Randal Hale
rjh...@northrivergeographic.com
(p) 423.653.3611
http://www.northrivergeographic.com
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] changing .gsb file for transformation

[Michael . Dodd]

I am trying to use the uk ordnance survey system in qgis along with other data 
in wgs84 and background imagery in other crs.  I have the relevant .gsb files 
for the ostn02 transformation (which currently use instead of the ostn15 
version) but can't see how to persuade qgis to use it instead of one of its 
several less accurate 'ballpark' transformation methods.  How to do this?
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority in relation to its secondary activity of credit broking.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] Anyone use UK Watsonian vice counties?

[Michael . Dodd]

Someone else has suggested an updated source here:
: https://github.com/BiologicalRecordsCentre/vice-counties
Am currently checking those polygons and so far they seem ok, they note there 
was an issue with the earlier version that I had been using, so the issue may 
now be solved.

Thanks

-Original Message-
From: Jonathan Moules  
Sent: 27 January 2020 15:54
To: Michael.Dodd ; 'qgis-user@lists.osgeo.org' 

Subject: Re: [Qgis-user] Anyone use UK Watsonian vice counties?

CAUTION: This mail comes from outside the University. Please consider this 
before opening attachments, clicking links, or acting on the content.

We're possibly talking at cross purposes.

I didn't follow the NBN link on that page, but instead used the the WFS URL ( 
http://geo.vliz.be:80/geoserver/wfs ) it provides which I connected to with 
QGIS and then added the Watsonian layer.

I suggested it because it may work for your purposes where your current dataset 
does not.


On 2020-01-27 15:47, Michael.Dodd wrote:
> Unfortunately that link goes back to NBN and a page that no longer exists so 
> presumably it is the same dataset.
> Qgis gives various errors depending on the analysis but always with those 8 
> VC's, when trying 'check validity' it says there is a problem with self 
> intersection. Not sure how to fix this as it is not obvious when you zoom in 
> on the polygons.
>
> From: Jonathan Moules 
> Sent: 27 January 2020 15:41
> To: Michael.Dodd ; 
> 'qgis-user@lists.osgeo.org' 
> Subject: Re: [Qgis-user] Anyone use UK Watsonian vice counties?
>
>
> CAUTION: This mail comes from outside the University. Please consider this 
> before opening attachments, clicking links, or acting on the content.
>
> Hi Michael,
>
> There is a WFS with them in that works in QGIS:
>
> https://www.geoseer.net/rl.php?ql=f64d2064355b5bdb=1=watsonian
>
> Not tried them for analysis or exporting them, but may be worth a try.
>
> Cheers,
>
> Jonathan
>
>
> On 2020-01-27 15:12, Michael.Dodd wrote:
>
> I have downloaded the set of polygons that was digitised by NBN. Then 
> converted to wgs84 but when I try to use the polygons, 8 of them: West 
> Norfolk, Herefordshire, Montgomeryshire, Shropshire, West Ross & Cromarty, 
> Orkney, Outer Hebrides, and Zetland do not work in analysis. Qgis says there 
> is a problem with those ones but says the rest are ok.
>
>
>
> Anyone else had similar issues and/or found ways to fix these?
>
> -- The Open University is incorporated by Royal Charter (RC 000391), an 
> exempt charity in England & Wales and a charity registered in Scotland (SC 
> 038302). The Open University is authorised and regulated by the Financial 
> Conduct Authority in relation to its secondary activity of credit broking.
>
>
>
>
>
> ___
>
> Qgis-user mailing list
>
> Qgis-user@lists.osgeo.org
>
> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
>
> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
>
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] Anyone use UK Watsonian vice counties?

[Michael . Dodd]

Unfortunately that link goes back to NBN and a page that no longer exists so 
presumably it is the same dataset.
Qgis gives various errors depending on the analysis but always with those 8 
VC's, when trying 'check validity' it says there is a problem with self 
intersection. Not sure how to fix this as it is not obvious when you zoom in on 
the polygons.

From: Jonathan Moules 
Sent: 27 January 2020 15:41
To: Michael.Dodd ; 'qgis-user@lists.osgeo.org' 

Subject: Re: [Qgis-user] Anyone use UK Watsonian vice counties?


CAUTION: This mail comes from outside the University. Please consider this 
before opening attachments, clicking links, or acting on the content.

Hi Michael,

There is a WFS with them in that works in QGIS:

https://www.geoseer.net/rl.php?ql=f64d2064355b5bdb=1=watsonian

Not tried them for analysis or exporting them, but may be worth a try.

Cheers,

Jonathan


On 2020-01-27 15:12, Michael.Dodd wrote:

I have downloaded the set of polygons that was digitised by NBN. Then converted 
to wgs84 but when I try to use the polygons, 8 of them: West Norfolk, 
Herefordshire, Montgomeryshire, Shropshire, West Ross & Cromarty, Orkney, Outer 
Hebrides, and Zetland do not work in analysis. Qgis says there is a problem 
with those ones but says the rest are ok.



Anyone else had similar issues and/or found ways to fix these?

-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority in relation to its secondary activity of credit broking.





___

Qgis-user mailing list

Qgis-user@lists.osgeo.org

List info: https://lists.osgeo.org/mailman/listinfo/qgis-user

Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] Anyone use UK Watsonian vice counties?

[Michael . Dodd]

I have downloaded the set of polygons that was digitised by NBN. Then converted 
to wgs84 but when I try to use the polygons, 8 of them: West Norfolk, 
Herefordshire, Montgomeryshire, Shropshire, West Ross & Cromarty, Orkney, Outer 
Hebrides, and Zetland do not work in analysis. Qgis says there is a problem 
with those ones but says the rest are ok.

Anyone else had similar issues and/or found ways to fix these?
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority in relation to its secondary activity of credit broking.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] Is it possible to read in mysql spatial data into qgis

[Michael . Dodd]

The data are stored in rather awkward format with circles having centre and 
radius, rectangles with two corners and polygons with point pairs in brackets 
rather than long sets of points.  Is there a utility for taking this format and 
reading into qgis so it can be converted to more standard wkt or similar?
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority in relation to its secondary activity of credit broking.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] qgis 3.4 LTR for centos7

[Michael . Dodd]

Is qgis 3.4 available for CentOS 7?
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority in relation to its secondary activity of credit broking.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] setout using qgis or qfield or similar

[Michael . Dodd]

Is there any way to use qgis or qfield or any other opensource software to 
'setout' points in the field?


This is rather basic functionality for a gps but once you are trying to use an 
external antenna with differential corrections and an android device it becomes 
a lot more difficult it seems. So far have tried quite a number of bits of 
android software that should be able to do this but without success.  I have 
thousands of points recorded to cm level accuracy (using survey grade surveying 
equipment) but now want to transfer them to an android device e.g. smartphone 
or tablet with high accuracy external aerial connected via bluetooth and set 
the points out again.


The high quality aerial can connect to the android device ok but most of the 
bits of software I have tried (other than ESRI collector) won't pick up the 
data from the external aerial properly.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] wkt

[Michael . Dodd]

I have 1000+ geometries as shown below and need to find the area of each, some 
of them have more than one chunk to the polygon. The format is not wkt format 
but is probably convertable.  Is there a way to get these into qgis and do the 
area calculations?


1  
{"circles":[],"polygons":[[[61.438,-0.461],[57.491,-9.645],[55.00,-9.689],[54.6983,-11.579],[50.985177,-11.53],[51.06809,-6.56982],[49.0944,-6.56],[50.0914,-1.73],[50.48454,1.076],[52.90801,2.878]]],"rectangles":[]}


4  
{"circles":[],"polygons":[],"rectangles":[[[51.0951,0.03457],[51.094,0.033871]]]}
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] QGIS airlines: connecting airports with lines ?

[Michael . Dodd]

The code to do this kind of thing has been in qgis for long time e.g. I 
published this map 
http://zookeys.pensoft.net/articles.php?id=4633_type=element_type=2_id=14_name=
 back in 2015 and had drawn it in qgis long time before it was published.  The 
difference is that the lines are straight not curved but in my case I wanted 
straight lines.


From: Qgis-user  on behalf of Falk Huettmann 

Sent: 26 March 2017 00:06:18
To: qgis-user
Subject: [Qgis-user] QGIS airlines: connecting airports with lines ?


Hi there,

I have a question, if I may:

at the following website

http://openflights.org/data.html

there are these maps of airlines, connecting airports.

http://openflights.org/demo/openflights-routedb-2048.png

The actual map and code can apparently be bought,
but instead I am looking for a self-made solution (I do not like how people 
cash in on a GIS bottleneck).

Would you perhaps know how that map can be done, e.g.
in QGIS or related in an OpenGIS framework or code?

Thanks so much; kind regards
 Falk

___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] qgis 2.18.3 not installing on win 10

[Michael . Dodd]

I tried uninstalling and installing again using the stand alone installer.  
This gave the same error so I uninstalled it.


Then I tried the OSGEO4W installer but it did not install exactly where I asked 
it to, instead it made its own directory on Y (Y:\osgeo_download). It did start 
up once but after that it failed to start and instead gave the same error about 
missing .dll's even though they were present.  I think I had a problem similar 
to this several qgis versions ago but it was then resolved, now the issue seems 
to be back.


This is the \QGIS 2.18\bin\qgis.bat file:


@echo off
call "%~dp0\o4w_env.bat"
@echo off
path %OSGEO4W_ROOT%\apps\qgis\bin;%PATH%
set QGIS_PREFIX_PATH=%OSGEO4W_ROOT:\=/%/apps/qgis
set GDAL_FILENAME_IS_UTF8=YES
rem Set VSI cache to be used as buffer, see #6448
set VSI_CACHE=TRUE
set VSI_CACHE_SIZE=100
set 
QT_PLUGIN_PATH=%OSGEO4W_ROOT%\apps\qgis\qtplugins;%OSGEO4W_ROOT%\apps\qt4\plugins
start "QGIS" /B "%OSGEO4W_ROOT%"\bin\qgis-bin.exe %*

and this is the directory where the relevant .dll's are 
Y:\osgeo_download\apps\qgis\bin
but it says they are missing even though they are present in this directory.



From: Qgis-user  on behalf of Andre Joost 

Sent: 26 February 2017 16:23:38
To: qgis-user@lists.osgeo.org
Subject: Re: [Qgis-user] qgis 2.18.3 not installing on win 10

Am 25.02.2017 um 21:58 schrieb Michael.Dodd:
> Have been using qgis for years.  Just uninstalled 2.14 and installed
> 2.18.3 but it refused to start saying that qgis_app.dll,
> qgis_core.dll and qgis_gui.dll are all missing.
>
>
> Infact they are not missing, they are all present.  However it seems
> to be looking in the wrong place, think similar problem has occurred
> with one or two previous versions.  I am NOT installing on c: drive
> as it has little space but instead installing on y: drive.  This
> worked fine for version 2.14 and various other programs but with
> version 2.18.3 it does not work.
>
>

You could try the OSGEO4W installer. It lets you choose the root
directory where everything is installed to.

Or have a look at \QGIS 2.18\bin\qgis.bat and o4w_env.bat. The variable
OSGEO4W_ROOT might be set wrongly. You get it when you type set inside
the OSGEO4W Shell. Override the definition if necessary.

HTH
André Joost

___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] qgis 2.18.3 not installing on win 10

[Michael . Dodd]

Have been using qgis for years.  Just uninstalled 2.14 and installed 2.18.3 but 
it refused to start saying that qgis_app.dll, qgis_core.dll and qgis_gui.dll 
are all missing.


Infact they are not missing, they are all present.  However it seems to be 
looking in the wrong place, think similar problem has occurred with one or two 
previous versions.  I am NOT installing on c: drive as it has little space but 
instead installing on y: drive.  This worked fine for version 2.14 and various 
other programs but with version 2.18.3 it does not work.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] official plugins repository unavailable?

[Michael . Dodd]

Have just installed 2.18 and got the normal plugins I use but then wanted to 
try another one and got the message that the official plugins directory is 
unavailable, not sure if this is to do with the parameter value 2.18
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: http://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] distance of point to line for large dataset

[Michael . Dodd]

I am trying to calculate the distance from points to vector lines.  There are 
various ways of doing this when there are relatively few points and lines but 
my datset has 200,000 points and a large network of vector lines and none of 
the tools I have tried in qgis seem to get anywhere. I have also tried 
converting the lines to raster but not clear what resolution to use and with 
high resolution the problem also seems to be that it takes forever to do the 
calculation.  If the tools gave an indication as to how long it is likely to 
take that would be a help e.g. 12 hours but waiting 12 hours on the chance that 
somethign might happen and still nothing is very frustrating.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: http://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] information

[Michael . Dodd]

You need to use gridinquest to do it accurately

From: Qgis-user [mailto:qgis-user-boun...@lists.osgeo.org] On Behalf Of Gill 
Weyman
Sent: 19 February 2016 10:52
To: qgis-user@lists.osgeo.org
Subject: [Qgis-user] information

Hello
I am new to qgis and wondering how I translate a long list of Irish grid 
references to a map which has lat and long data?
Any pointing in the right direction would be appreciated.
Gill
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: http://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] Google to withdraw aerial images?

[Michael . Dodd]

Does anyone know if the aerial imagery that google provide, and which can be 
accessed into qgis projects, is being withdrawn?
Looking at google maps aerial imagery for UK, the aerial photos are now gone 
and instead replaced by some kind of horrible processed hybrid image.  This is 
of little or no use for ecological projects and I suspect looses its value in 
many other types of project.

Is it time to start a campaign to keep the original imagery and at least have 
it accessible via qgis or other systems.

I suspect Google think they know best so will convert all their imagery to this 
horrible processed version.
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: http://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] Continentality

[Michael . Dodd]

Can 'continentality' be derived just using gis with land masses and latitude 
and if so how using qgis?  I am not a meterologist/climate scientist. On one 
hand it would seem a simple thing to look at distances to the coast and assume 
bigger distance to coast = bigger temperature range = higher value of 
continentality but there is probably more to it than this with other regular 
factors large scale weather systems such as monsoons and topography playing a 
role?
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
List info: http://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] qgis and spatialite

[Michael . Dodd]

I am trying to use spatialite with qgis but can't get spatialite to recognise 
geometry columns even though qgis can display the same data when given a .csv 
or shapefile. The data consist of a large spreadsheet including lat and long 
columns, this reads and displays fine in qgis.

When I put this into spatialite I can't get spatialite to recognise that two of 
the columns are lat and long (I have only just started using spatialite).

I can't convert the full data in qgis into a shapefile and import that into 
spatialite as spatialite refuses to accept the shapefile saying it contains 
errors or wrong kind of data.  The actual shapefile seems fine as it opens 
again in qgis.

I can chop the datafile down to just a few columns containing the coordinates 
and a key, convert that to shapefile and import that into spatialite. I can 
also import the full spreadsheet into spatialite as a text file but I can't see 
a way of joining the two together so that the two separate tables both have the 
geometry by linking on the key column even though I can see the dialogue that 
deals with links between tables.
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] Open Layers Plugin - Question about Google Maps/Earth Policy

[Michael . Dodd]

I think the issue here is that google did not take the aerial imagery 
themselves they just buy it in/license it from 3rd parties and google do not 
have agreements with these 3rd parties to let it be used for all purposes so 
they can't say other people can use it in this way.  Presumably Microsoft have 
different sorts of agreements with the people who take the aerial imagery.

From: qgis-user-boun...@lists.osgeo.org [qgis-user-boun...@lists.osgeo.org] on 
behalf of Bernd Vogelgesang [bernd.vogelges...@gmx.de]
Sent: Tuesday, September 22, 2015 10:43 AM
To: QGIS Support; Rachel du Plessis
Subject: Re: [Qgis-user] Open Layers Plugin - Question about Google Maps/Earth 
Policy

Am 22.09.2015, 10:27 Uhr, schrieb Rachel du Plessis :

Hello,

I am operating on OS X version 10.9.5 and am using QGIS 2.6.1 - Brighton. I am 
using the Open Layers Plugin version 1.3.6 (Google maps) to create shapefiles 
and edit existing shapefiles over the Google map plugin data. I happened notice 
that in the Google Maps/Earth Permissions page under "Geo Permissions" a FAQ 
was posed:

http://www.google.com/permissions/geoguidelines.html

"I'd like to trace a map using your imagery. Can I?" The response: "You may not 
use Google Maps or Google Earth as the basis for tracing your own maps or other 
geographic content." My question: Does QGIS have some sort of agreement with 
Google Maps/Earth which allow the mapping community to use the plugin they have 
provided? Can anyone assist?

Thanks,
Rachel
East London, South Africa

Hi,

I don't think that there is an agreement with Google.
But I think to remember that the Bing-maps are available for georeferencing, 
cause they are used in OpenStreetMap editors (But I don't know if this only 
allowed for OpenStreetMap data)

Apart from those "legal" issues, I recommend you to try the new 
QuickMapServices plugin.

Bernd


--
Bernd Vogelgesang
Siedlerstraße 2
91083 Baiersdorf/Igelsdorf
Tel: 09133-825374
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] Saving qgs project file takes forever on VPN - no problem with data

[Michael . Dodd]

And what happens if more than one person at once tries to edit the project on 
the server. There are 3 people all working on one project, we plan to do it in 
turns, what happens if we make a mistake and try to open the main project or 
edit some of the layers on the server two people at the same time via vpn (we 
are physically in different parts of the country).

From: qgis-user-boun...@lists.osgeo.org [qgis-user-boun...@lists.osgeo.org] on 
behalf of magerlin [m...@ramboll.dk]
Sent: Tuesday, September 15, 2015 10:23 AM
To: qgis-user@lists.osgeo.org
Subject: Re: [Qgis-user] Saving qgs project file takes forever on VPN - no 
problem with data

Just a minute ago I edited my post by adding that AutoSaver is just as slow
:-(



-
Regards Morten

Currently using Qgis 2.10.1 (OSGeo4),
Windows 7, 64bit
--
View this message in context: 
http://osgeo-org.1560.x6.nabble.com/Saving-qgs-project-file-takes-forever-on-VPN-no-problem-with-data-tp5224216p5224245.html
Sent from the Quantum GIS - User mailing list archive at Nabble.com.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] Saving qgs project file takes forever on VPN - no problem with data

[Michael . Dodd]

I know at least two others who have the same issue via vpn and no i don't know 
why it happens. it is also not clear what would happen if you close the vpn 
connection before the project is closed.

From: qgis-user-boun...@lists.osgeo.org [qgis-user-boun...@lists.osgeo.org] on 
behalf of magerlin [m...@ramboll.dk]
Sent: Tuesday, September 15, 2015 8:45 AM
To: qgis-user@lists.osgeo.org
Subject: [Qgis-user] Saving qgs project file takes forever on VPN - no  problem 
with data

Sometimes I work via VPN on a server at my job with both qgs project file and
shapefiles on the company server.

Working with the data (= shapefiles) work fine, but saving the project takes
forever - lately a 600 kb project file took about 15 minutes to save. I can
see in the windows file manager how the filesize on the server grows very
slowly after having pressed save.

I can copy a 600 kb file to the company server in a few seconds so the
general connection is ok.

Anybody else experiencing this?
Anybody got a clue why?



-
Regards Morten

Currently using Qgis 2.8.1 (OSGeo4),
Windows 7, 64bit
--
View this message in context: 
http://osgeo-org.1560.x6.nabble.com/Saving-qgs-project-file-takes-forever-on-VPN-no-problem-with-data-tp5224216.html
Sent from the Quantum GIS - User mailing list archive at Nabble.com.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] connecting to wms

[Michael . Dodd]

How to connect qgis to wms and similar services? I have seen various services 
that I would like to connect to e.g.
http://directory.spatineo.com/service/25565/

however when trying to add the web address shown
http://lasigpublic.nerc-lancaster.ac.uk/arcgis/services/LandCoverMap/LCM2007_GB_25m_V2/MapServer/WmsServer

to either the add layer to wms or metasearch menus it gives an error (error 203 
or similar).

Adding wms used to be very simple but I am either now doing things wrong or the 
more recent versions of qgis seem to make this more complex.
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England & Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] CAD like drawings in qgis

[Michael . Dodd]

Is it possible to do CAD like drawings in qgis, for example the ground plan of 
a house plus the elevations?  I know qgis is not a CAD package and that you 
could do a non-earth map in qgis to show the ground plan but I was wondering 
whether there is any simple CAD like ability via a plugin. If this is not 
possible is there an opensource CAD program that might link to qgis so that it 
can pick up the ground plan and surrounding area?
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] save as .gpx?

[Michael . Dodd]

Has anyone got the .gpx files that qgis produces to work in apps such as OSMAND?

.gpx files produced by other programs seem to work ok with OSMAND but those 
from qgis just show up as dots and it is not possible to label the points even 
though the point labels are present in the .gpx file.

It appears to be a formatting issue with the .gpx files from qgis, I raised it 
a year or two ago but the problem still seems to be present.  It is very 
annoying when trying to produce maps for people who need to go into the field 
to specific points, they don't know which point to aim for as they just see a 
screen of dots with no indication which is which.
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] save as .gpx?

[Michael . Dodd]

Actually I have the opposite problem, I want to show the point labels, my file 
only has points in it.  I can see the labels in the .gpx file if I look at it 
with notepad++ but the labels will not show up in other programs such as osmand 
or indeed google earth.

From: ralfwessels [g...@ralf-wessels.de]
Sent: Friday, June 05, 2015 2:33 PM
To: qgis-user@lists.osgeo.org
Subject: Re: [Qgis-user] save as .gpx?

Hi Michael,

I had the same problem saving gpx in QGIS and using it with OsmAND.
I figured out to set the Layeroption  FORCE_GPX_TRACK = YES when exporting
from QGIS to see lines in OsmAND and not points.
ralf



--
View this message in context: 
http://osgeo-org.1560.x6.nabble.com/save-as-gpx-tp5209401p5209406.html
Sent from the Quantum GIS - User mailing list archive at Nabble.com.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] blue marble and similar wms

[Michael . Dodd]

I am looking for a creative commons or similar background image to use with OSM 
vector data. There are options via openlayers and wms but can't find one that 
has suitable imagery without labels.
I am looking for something only at low resolution for background to New Zealand 
map.  There are loads of possibilities via LINZ but none provide a general topo 
image or similar suitable for whole country that looks reasonable as a map 
background (e.g. the terrain relief map is in big blocks and do not seem to be 
able to select out the coastline using vector to tidy up the edges, qgis raster 
clipper simply says the coastline shapefile or any other shapefile will not 
work to cut the raster).
Is there a wms providing blue marble data or a way of georeferencing the 
downloadable blue marble image files?
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] contour plugin and dependencies

[Michael . Dodd]

Have tried removing qgis (the full package) and installing via osgeo4w making 
sure all the correct bits were there.  it appears there are some bugs as when i 
was deleting the full package i saw the correct parts such as numpy etc being 
deleted even though the plugin said they were not present.

anyway first attempt via osgeo4w the contour plugin complained that matplotlib 
was missing, infact it was not missing but i reinstalled it again anyway.  this 
time contour plugin said everything was present and correct.  unfortunately it 
still failed to work giving a python error saying it could not parse the data.  
as far as i can see there is nothing wrong with the data, it is a simple small 
datafile that other parts of the program deal with ok.

From: Chris Crook [ccr...@linz.govt.nz]
Sent: Wednesday, March 04, 2015 3:00 AM
To: Michael.Dodd
Subject: RE: [Qgis-user] contour plugin and dependencies

Hi Michael

It is very likely that it is due to missing dependencies.  The contour plugin 
relies on python numpy and matplotlib modules. I'm pretty sure these can be 
installed from osgeo4w, though its been a while since I've done so (I'm working 
on linux).  I've no idea why the osgeo4w installer did not work - possibly a 
local firewall or web proxy issue?

Thanks for noting that the error message is not clear.  If you think it is not 
numpy or matplob missing (which I guess will show as an import error) could you 
let me know please?

Thanks
Chris

From: Michael.Dodd [michael.d...@open.ac.uk]
Sent: 04 March 2015 04:41
To: 'qgis-user@lists.osgeo.org'
Subject: [Qgis-user] contour plugin and dependencies

I am using qgis 2.8.1 and contour 1.3 on win8.1 64bit but plugin comes up with 
a python error and does not produce any contours.

I assume the error is due to missing dependencies although it does not say 
this.  If it is due to missing python dependencies then how do you load these, 
is it via osgeo4w installer?  when i tried to download osgeo4w installer it did 
not seem to be available (web link never connected).
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.

This message contains information, which may be in confidence and may be 
subject to legal privilege. If you are not the intended recipient, you must not 
peruse, use, disseminate, distribute or copy this message. If you have received 
this message in error, please notify us immediately (Phone 0800 665 463 or 
i...@linz.govt.nz) and destroy the original message. LINZ accepts no 
responsibility for changes to this email, or for any attachments, after its 
transmission from LINZ. Thank You.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] contour plugin and dependencies

[Michael . Dodd]

I am using qgis 2.8.1 and contour 1.3 on win8.1 64bit but plugin comes up with 
a python error and does not produce any contours.

I assume the error is due to missing dependencies although it does not say 
this.  If it is due to missing python dependencies then how do you load these, 
is it via osgeo4w installer?  when i tried to download osgeo4w installer it did 
not seem to be available (web link never connected).
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] FW: contour plugin and dependencies

[Michael . Dodd]

From: Michael.Dodd
Sent: Tuesday, March 03, 2015 5:23 PM
To: afdal fs
Subject: RE: [Qgis-user] contour plugin and dependencies

how do you do this?

From: afdal fs [afda...@gmail.com]
Sent: Tuesday, March 03, 2015 5:00 PM
To: Michael.Dodd
Subject: Re: [Qgis-user] contour plugin and dependencies

you must get python modules first

2015-03-03 22:41 GMT+07:00 Michael.Dodd 
michael.d...@open.ac.ukmailto:michael.d...@open.ac.uk:
I am using qgis 2.8.1 and contour 1.3 on win8.1 64bit but plugin comes up with 
a python error and does not produce any contours.

I assume the error is due to missing dependencies although it does not say 
this.  If it is due to missing python dependencies then how do you load these, 
is it via osgeo4w installer?  when i tried to download osgeo4w installer it did 
not seem to be available (web link never connected).
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.

___
Qgis-user mailing list
Qgis-user@lists.osgeo.orgmailto:Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] what is the best way to keep qgis up to date?

[Michael . Dodd]

Qgis is updated frequently but what is the best way to keep it up to date on 
your local machine?

I have gone through perhaps 10 different versions either using the standalone 
or OSgeo.  OSgeo used to work fine but then had more problems with all the 
different settings and went through a period where everything had to be removed 
from the machine before any updates were possible.  Went back to standalone 
which also had to be removed but was easier to do.  Have 4 different machines 
each with a different OS so it would be nice if there were some more automated 
way of keeping things fairly up to date.

Dr Mike Dodd
Department of Environment, Earth and Ecosystems
The Open University
Walton Hall
Milton Keynes
MK7 6AA

http://www.ispot.org.uk/
http://www.treezilla.org/
http://www.floodplainmeadows.org.uk/
http://www.amanita-photolibrary.co.uk/HTML_Trees/








-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] is it possible to change field type

[Michael . Dodd]

When creating polygons I suddenly realised that I need to change the field type 
from integer to text, however this does not seem possible in layer properties 
and the help does not mention this.  Is there some other way of changing the 
type or is it fixed once you have started entering data?
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] Is the openlayers 'plugin' still broken on 2.6.1 64bit windows8?

[Michael . Dodd]

Have just noticed that the plugin in the latest version of the qgis 2.6.1 
download was out of date so updated plugin and it does now work. Obviously the 
plugin was fixed very recently.

From: Michael.Dodd [michael.d...@open.ac.uk]
Sent: Tuesday, December 16, 2014 9:46 AM
To: 'qgis-user@lists.osgeo.org'
Subject: [Qgis-user] Is the openlayers 'plugin' still broken on 2.6.1 64bit 
windows8?

It seems to work with bing and osm and half work with google but not work at 
all with most of the others.
I say half work with google as google physical works but google satellite only 
shows southern hemisphere.

This is using the web menu in 2.6.1 installed via osgeo4w not the standalone 
installer but accepting all the dependencies.
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] Interpolation

[Michael . Dodd]

Any suggestions as to the best way to survey and interpolate ridge and furrow 
grassland that is not on a flat plane?
I have tried various methods without success.

The ridge and furrow area that I want to map is about 120mx120m, the ridge and 
furrow pattern is distinct with about 0.5m or difference between ridge ht and 
furrow base but the pattern has a slight curve towards one end and the land is 
not flat.  If you are not sure what ridge and furrow looks like then there is 
an example at 51.9827, -0.9135, the stripes are clearly visible on the google 
earth image.

Mapping can be done with cm level dgps but does this require many tens of 
thousands of points to be recorded. Or can fewer points be recorded and qgis 
interpolation somehow be told to interpolate along the ridge and furrow then 
fill in the area between them with some sort of curve. The actual curve is also 
problematic as the ridge top tends to be flattened and not a smooth sine wave.  
I don't have good LIDAR of the area but even that resolution may not be good 
enough.

-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] Interpolation

[Michael . Dodd]

Yes had thought about this and nearly got Leica to test out their latest laser 
scanner a couple of years ago but land owner was frightened it might cause some 
kind of damage to the area so it never happened.



From: Andrew Harfoot [a...@geodata.soton.ac.uk]
Sent: Thursday, September 18, 2014 2:46 PM
To: qgis-user@lists.osgeo.org
Subject: Re: [Qgis-user] Interpolation

Hi Michael,

Off the top of my head, but have you looked into a laser scanner mounted on 
some sort of aerial platform such as a cherry picker? Not sure whether the 
platform would be stable enough.

Alternatively a low level UAV flight may provide a detailed enough DTM through 
stereo imagery analysis.

Cheers,

Andy

On 18/09/2014 10:43, Michael.Dodd wrote:
Any suggestions as to the best way to survey and interpolate ridge and furrow 
grassland that is not on a flat plane?
I have tried various methods without success.

The ridge and furrow area that I want to map is about 120mx120m, the ridge and 
furrow pattern is distinct with about 0.5m or difference between ridge ht and 
furrow base but the pattern has a slight curve towards one end and the land is 
not flat.  If you are not sure what ridge and furrow looks like then there is 
an example at 51.9827, -0.9135, the stripes are clearly visible on the google 
earth image.

Mapping can be done with cm level dgps but does this require many tens of 
thousands of points to be recorded. Or can fewer points be recorded and qgis 
interpolation somehow be told to interpolate along the ridge and furrow then 
fill in the area between them with some sort of curve. The actual curve is also 
problematic as the ridge top tends to be flattened and not a smooth sine wave.  
I don't have good LIDAR of the area but even that resolution may not be good 
enough.

-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.


___
Qgis-user mailing list
Qgis-user@lists.osgeo.orgmailto:Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user



--
Andy Harfoot

GeoData Institute
University of Southampton
Southampton
SO17 1BJ

Tel:  +44 (0)23 8059 2719
Fax:  +44 (0)23 8059 2849

www.geodata.soton.ac.ukhttp://www.geodata.soton.ac.uk

___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] Interpolation

[Michael . Dodd]

Sounds very interesting.
I am trying to map the ridge and furrow so that I can see how plants are 
distributed on them.  I have been recording the plants with the high accuracy 
gps so have these locations to cm level accuracy but not been able to put them 
on a model of the RF itself.  If the photography is high enough resolution and 
taken from low enough the individual plants themselves might show up.

From: Alex Mandel [tech_...@wildintellect.com]
Sent: Thursday, September 18, 2014 7:21 PM
To: Michael.Dodd; Andrew Harfoot; qgis-user@lists.osgeo.org
Subject: Re: [Qgis-user] Interpolation

All the rage at http://2014.FOSS4g.org - Structure From Motion.
Basically using airphotos to build a 3d mesh model of an area with
classic photogrammetry calculations automated. Photos need not be from
directly overhead.

Specifically see the talks by Stephen Mather and Aaron Racicot.

The open source option are not quite 100% there yet (Stephen's talk on
OpenDroneMap) but there is a $170 program PhotoScan that's an option
(See Aaron's talk).

Thanks,
Alex

PS: I use cheap cameras on Kites for sub-centimeter photography.

On 09/18/2014 10:58 AM, Michael.Dodd wrote:
 Yes had thought about this and nearly got Leica to test out their latest 
 laser scanner a couple of years ago but land owner was frightened it might 
 cause some kind of damage to the area so it never happened.


 
 From: Andrew Harfoot [a...@geodata.soton.ac.uk]
 Sent: Thursday, September 18, 2014 2:46 PM
 To: qgis-user@lists.osgeo.org
 Subject: Re: [Qgis-user] Interpolation

 Hi Michael,

 Off the top of my head, but have you looked into a laser scanner mounted on 
 some sort of aerial platform such as a cherry picker? Not sure whether the 
 platform would be stable enough.

 Alternatively a low level UAV flight may provide a detailed enough DTM 
 through stereo imagery analysis.

 Cheers,

 Andy

 On 18/09/2014 10:43, Michael.Dodd wrote:
 Any suggestions as to the best way to survey and interpolate ridge and furrow 
 grassland that is not on a flat plane?
 I have tried various methods without success.

 The ridge and furrow area that I want to map is about 120mx120m, the ridge 
 and furrow pattern is distinct with about 0.5m or difference between ridge ht 
 and furrow base but the pattern has a slight curve towards one end and the 
 land is not flat.  If you are not sure what ridge and furrow looks like then 
 there is an example at 51.9827, -0.9135, the stripes are clearly visible on 
 the google earth image.

 Mapping can be done with cm level dgps but does this require many tens of 
 thousands of points to be recorded. Or can fewer points be recorded and qgis 
 interpolation somehow be told to interpolate along the ridge and furrow then 
 fill in the area between them with some sort of curve. The actual curve is 
 also problematic as the ridge top tends to be flattened and not a smooth sine 
 wave.  I don't have good LIDAR of the area but even that resolution may not 
 be good enough.

 -- The Open University is incorporated by Royal Charter (RC 000391), an 
 exempt charity in England  Wales and a charity registered in Scotland (SC 
 038302). The Open University is authorised and regulated by the Financial 
 Conduct Authority.


 ___
 Qgis-user mailing list
 Qgis-user@lists.osgeo.orgmailto:Qgis-user@lists.osgeo.org
 http://lists.osgeo.org/mailman/listinfo/qgis-user



 --
 Andy Harfoot

 GeoData Institute
 University of Southampton
 Southampton
 SO17 1BJ

 Tel:  +44 (0)23 8059 2719
 Fax:  +44 (0)23 8059 2849

 www.geodata.soton.ac.ukhttp://www.geodata.soton.ac.uk




 ___
 Qgis-user mailing list
 Qgis-user@lists.osgeo.org
 http://lists.osgeo.org/mailman/listinfo/qgis-user


___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] OpenLayers available in 2.4?

[Michael . Dodd]

However did you notice whether the accuracy was maintained when you zoomed in a 
lot with the old version of openlayers, from memory it seemed to jump to 
slightly wrong place (compared to other layers) when you zoomed in too far.

-Original Message-
From: Pedro [mailto:pedro.fe...@gmail.com]
Sent: 04 August 2014 14:41
To: qgis-user@lists.osgeo.org
Subject: Re: [Qgis-user] OpenLayers available in 2.4?

One difference between the QGIS 2.4 OpenLayers  and the previous one is the 
zoom level where I can get the maps.

For example, in previous version of QGIS, with maps from google or bing I had 
maps up to scales of 1:100, with openlayers in QGIS 2.4 nothing less than 
1:1150 ... a big difference.

Is it configurable in some QGIS option?

Thanks,
Pedro



--
View this message in context: 
http://osgeo-org.1560.x6.nabble.com/OpenLayers-available-in-2-4-tp5153299p5154967.html
Sent from the Quantum GIS - User mailing list archive at Nabble.com.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] GPS issue on android tablet

[Michael . Dodd]

I would echo Mike's comments here.
You could try the google background imagery, in a few places in UK where I have 
checked their error is around 2m or better although in some places it can be a 
lot worse than this so it depends where you are as to how reliable this imagery 
is.

'Professional level' dgps can often give 1-2cm accuracy in real time using 
correction services such as Smartnet (in UK and parts of Europe) but the kit is 
expensive and you have to pay a license to use the correction service.
Mike

From: Mike Shand [mike.sh...@glasgow.ac.uk]
Sent: Wednesday, June 04, 2014 10:36 AM
To: qgis-user@lists.osgeo.org
Subject: Re: [Qgis-user] GPS issue on android tablet

Zoltan,

I suggest you create a Csv file and plot the points on a large scale map
or hi-res satellite image.
You say varies very widely, a quick check indicated the max. variation
between your points is approx 8m and the min. approx 1m.

I would say if you are getting 3m GPS accuracy that is pretty good if
you are outside the US or Europe.  I assume you are using a dedicated
GPS unit attached to your Tablet and not a built-in GPS on your Tablet.
Bear in mind that the 3m accuracy deviation (imagine a 3m radius circle
from where you mark the point) can be in any direction, so if you are 3m
E out with first reading and 3m W with the second reading the error
between the point could be 6m.

Mike


On 04/06/2014 10:14, Zoltan Szecsei wrote:
 On 2014/06/04 11:07, Giuseppe De Marco wrote:
 hello, I've been using Qgis on android tablet (samsung galaxy tab 2)
 and I've been experimenting GPS connection.
 The issue is that even if Qgis finds and use several satellites (9 or more)
 precision never gets under 3.0 meters but what is strange is that
 coordinates value fro the same spot varies very widely:
 TimeCoordinates   Altitude
 14:39:36   41.69528959 13.26464738  343.1
 14:39:54   41.69529880 13.26466761  341.8
 14:40:06   41.69528519 13.26470222  340.4
 14:41:18   41.69528944 13.26472418  341.1
 14:41:42   41.69529608 13.26471821  341.8
 14:41:54   41.69530621 13.26470892  342.5

 I have colleagues who have experienced the same.
 Has anyone else experienced the same issue?
 Is that depending on GPS device or could it be a software related
 issue?

 There are probably 1 reasons for this.
 I am surprised that you even think you are getting sub 5m accuracy.
 Please plot the points on a cadastral map (or some basemap that is
 guaranteed accurate) and see what you are really getting.
 You also don't say whether you are in a tree'd or urban (or whatever)
 area - but observing 9 satellites suggests somewhere in the open.

 For professional GPSes, to get sub 10cm accuracy, you need to observe
 for 30-60 minutes, and do post processing.

 I am not a surveyor, so my info may be not 100% - Please can a surveyor
 or someone well experienced in these issues chip in.

 Regards,
 Zoltan


___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302). 
The Open University is authorised and regulated by the Financial Conduct 
Authority.
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] Point relocation

[Michael . Dodd]

Is it possible to use qgis on smartphone to relocate stored points on a map?
We have a large number of accurately recorded positions (dgps) and want to make 
them available to a small group of people who just have smartphones.  
Preferably there would be a map background to help them locate the positions 
but certainly need arrows and a way of navigating when approaching close to the 
position to avoid the location jumping all over the place.  This sounds like a 
job for one of the geocaching apps or similar but having looked through quite a 
number of these I have not been able to find anything suitable as they either 
want you to upload points to a server and make them public (which would not be 
appropriate in our case) or have specific non standard formats or have other 
issues e.g. that make it difficult to label our positions appropriately.  I 
have also tried a few non geocaching apps that claim to find positions e.g. 
satnav type for car navigation but these generally don't work well to take you 
to the exact position in the field.  Our original data are in qgis 
 so simply having a plugin that would do this seems a good idea so long as qgis 
will run on the android smartphone.  The locations are mainly in UK but some 
are overseas, they use a variety of different coordinate systems but all can be 
converted to wgs84 lat long.
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302).
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] Tablet vs GPS accuracy

[Michael . Dodd]

I did a considerable amount of testing comparing conventional gps devices and 
smartphones and some more advanced gps devices.  All compared to cm level dgps 
locations.
One factor to consider is that smartphones tend to be mass produced in much 
larger numbers than separate gps devices so they can potentially have the 
latest most accurate chips etc.  as far as i recall towers only affect speed of 
first location not accuracy as the location calculated just from tower is much 
less accurate than from the gps itself.  I also recall reading somewhere that 
one or two models of smartphone physically have the technology in them to do 
0.5m accuracy but this ability is switched off at the moment.

From: Blumentrath, Stefan [stefan.blumentr...@nina.no]
Sent: Thursday, April 03, 2014 12:59 PM
To: Leo Kris Palao; QGIS Mailing List
Subject: Re: [Qgis-user] Tablet vs GPS accuracy

Hei Leo,

Unfortunately I do not recall where I read comparison of “proper GPS” and 
Smartphones regarding precision. But as far as I remember precision difference 
depends very much on where you are.
Smartphones (and also tablets I guess) make also use of the cell towers / 
access points to the mobile network for positioning.
So, if you are working in towns or populated areas you get probably comparable 
precision to a commercial GPS (a few meters difference). But if you are in 
remote areas, difference can be more significant 20m and more…

Others please correct me if I am wrong…

And as Zoltan writes: what is “good” (or more precise “suitable”) depends on 
your needs…

Cheers
Stefan
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302).
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] Tablet vs GPS accuracy

[Michael . Dodd]

I agree with the points Richard has made here.  I mentioned in an earlier 
message on this topic that I'd done a lot of testing with smartphones vs 
consumer gps  see
http://www.open.ac.uk/blogs/otih/?p=466 for details on some of the tests.

Also tested consumer grade gps and a range of other surveying techniques with 
results and discussion shown here:
http://oro.open.ac.uk/30066/

From: Richard McDonnell [richard.mcdonn...@opw.ie]
Sent: Thursday, April 03, 2014 4:09 PM
To: Leo Kris Palao
Cc: QGIS Mailing List
Subject: Re: [Qgis-user] Tablet vs GPS accuracy

Hi,
It all boils down to the level of accuracy your job requires, Commercial or 
Survey Grade GNSS (Global Navigation Satellite System) now utilises NRTK 
(Network Real Time Kinematic) which can produce sub centimetre accuracies. We 
have found that the accuracies is often too good, with our surveys conflicting 
with Maps. We have seen +-40mm accuracies in the field, where a stake in the 
ground is surveyed and the kit can take us right back to the point days later, 
to within 40mm. it is worth noting that Survey grade GPS has a stated accuracy 
of sub meter without NRTK.
The next step down in accuracies would be GPS enabled Field Computers, again a 
dedicated kit but hand held form factor, the Trimble Geo-Explorer 7 is an 
example of one of these. They now also have the ability to utilise NRTK, 
bringing there accuracies to within 0.5m (or better).
The issue with phones and tablets is that, unlike dedicated systems, you have 
less control over how the coordinates are recorded. They don't take into 
account things like multipath (GPS signal bouncing off buildings, Ground etc.)  
The number of satellites (the more the better) Most survey kits wont record a 
point with less than 5 satellites.
There is a way to get an idea of the accuracy for your proposed device. Take 
several readings over a day (7 or more) of 2 fixed points approx 50m apart,  
every day, for a week. Then compare the results. you will have a spread of 
points, none of which are likely to be perfect, but will give you an idea of 
the accuracies of the device, the spread of the points being your expected 
error. A shorter test over a day would yield similar results but over a week, 
you would have a more comprehensive result. I have seen some tests, where 
accuracies with an i-Phone were stated as +-3m.
One other thing you should all note when using a phone or similar device to 
record your location, Use the native Latitude and Longitude to record the 
position, don't use the device to transform the coordinates to some other CRS. 
Use a dedicated CRS Transformation tool on a desktop/Laptop computer to convert 
to your desired CRS. Handhelds are not suitable for that purpose.
I hope this helps!!
Regards,

Richard.

On 03/04/2014 12:30, Leo Kris Palao wrote:

Hi QGIS Users,

I would like to inquire if there are some user that already assessed the 
positioning (location) accuracy of tablet vs commercial gps. We would like to 
use qgis android for fieldwork. We would also like to try qmap.

Thanks,
Leo



___
Qgis-user mailing list
Qgis-user@lists.osgeo.orgmailto:Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user



**

Email Disclaimer: http://www.opw.ie/en/disclaimer/

**



-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302).
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

[Qgis-user] point sampling tool is there anyway to speed it up and keep it going

[Michael . Dodd]

The point sampling plugin can be very effective but is slow when dealing with a 
large number of points and a complex area to be sampled e.g. hundreds of 
thousands of points on a relatively detailed map of world countries.  I can 
cope with it being slow by just accepting it will take all day to run BUT it 
never completes because there is always something that happens on the pc that 
stops it, the last time it happened after about 4 hours with a couple more 
hours to run.  If you try to use any other program on the pc then the tool 
stops and also freezes qgis.  am currently running qgis 2.0.1 on windows7 64bit 
with quite a lot of ram although i note it never uses more than about 13% of 
the total ram.  I used to run the tool with earlier versions of qgis on 
windowsXP and had the same issue with it stopping if any other program was 
opened on the pc.
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302).
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] point sampling tool is there anyway to speed it up and keep it going

[Michael . Dodd]

Thanks for the suggestion, I tried it a couple of times but after 1000-2000 
points it crashed (different number of points each time I tried).  It was very 
quick doing this in a few seconds whereas point sampling had taken several 
minutes for this number, however point sampling went on for hours until it 
crashed with about 230,000 done of the 300,000 total points.

From: Anita Graser [anitagra...@gmx.at]
Sent: Friday, January 10, 2014 7:44 PM
To: qgis-user@lists.osgeo.org; Michael.Dodd
Subject: Re: [Qgis-user] point sampling tool is there anyway to speed it up and 
keep it going

Hi Michael,

Try the SAGA implementation (through Processing). It's much faster, as
described in
http://anitagraser.com/2013/10/02/add-polygon-attributes-to-points-vs-join-attributes-by-location/

Best wishes,
Anita


Am 10.01.2014, 19:41 Uhr, schrieb Michael.Dodd michael.d...@open.ac.uk:

 The point sampling plugin can be very effective but is slow when dealing
 with a large number of points and a complex area to be sampled e.g.
 hundreds of thousands of points on a relatively detailed map of world
 countries.  I can cope with it being slow by just accepting it will take
 all day to run BUT it never completes because there is always something
 that happens on the pc that stops it, the last time it happened after
 about 4 hours with a couple more hours to run.  If you try to use any
 other program on the pc then the tool stops and also freezes qgis.  am
 currently running qgis 2.0.1 on windows7 64bit with quite a lot of ram
 although i note it never uses more than about 13% of the total ram.  I
 used to run the tool with earlier versions of qgis on windowsXP and had
 the same issue with it stopping if any other program was opened on the
 pc.
 -- The Open University is incorporated by Royal Charter (RC 000391), an
 exempt charity in England  Wales and a charity registered in Scotland
 (SC 038302).
 ___
 Qgis-user mailing list
 Qgis-user@lists.osgeo.org
 http://lists.osgeo.org/mailman/listinfo/qgis-user


--
anitagraser.com
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302).
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user

Re: [Qgis-user] installation problem with OSGeo4W Advanced Installer under windows 7

[Michael . Dodd]

I have a similar problem.  Just trying the 'advanced install' on 2 machines: 
win32 xp and win64 with win7.  The win7 version stops download half way through 
and gives up.  The win 32xp version stops download at 95%+ but then says it 
will install anyway (which is it currently doing).  Not had problems like this 
with any previous versions of qgis.

-Original Message-
From: Anne Quesnel [mailto:aques...@univ-lille2.fr]
Sent: 25 September 2013 15:36
To: Qgis-user@lists.osgeo.org
Subject: [Qgis-user] installation problem with OSGeo4W Advanced Installer under 
windows 7

Dear all,
objet: installation problem for advanced GIS under windows 7

After several tests with the downloaded file called osgeo4w-setup.exe, I met 
an access problem error : refused access to the mount I ve disconnected the 
antivarus software

Do you have any idea to resolve this problem?


Thank you for your attention
BW
AQ


--
Quesnel Anne - Dr en Géographie quantitative; Géomatique en Santé.
http://quesnela.free.fr/
Mobile: 06 58 06 68 08
Télécharger ma thèse de doctorat
http://tel.ccsd.cnrs.fr/documents/archives0/00/00/96/22/index_fr.html
--


___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user
-- The Open University is incorporated by Royal Charter (RC 000391), an exempt 
charity in England  Wales and a charity registered in Scotland (SC 038302).
___
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user