On 05/16/2011 06:01 PM, [email protected] wrote:
Click plugins, manage plugins then locate and enable Georeferencer
(you may need to download Python plugins first)
Use this tool to click on points on the map, & specify/enter the UTM
coordinates for these points.
Do this for several points scattered throughout the image. Once done
(accurately!) QGIS will correctly locate the image on the map, and
therefore properly place any points or lines overlaid on it.
This is not the only way, but is perhaps the simplest.
HTH,
Brent Wood
Hello Dave,
I believe that QGIS is in fact the right tool for you to use.
In a normal case you would need to load both .map file in QGIS. Then
using the georeferencer plugin, load the JPG and start giving known
coordinates (the ozi file points, using the "From map canvas tool")
to places on your image. After at you will be able to georeference
the imagem and load it in QGIS.
With a bit of luck, all the points in your ozi file are in the same
coordinate system (It would be very strange if it didn't...),
probably WGS84 geographic coordinates and you don't need to worry at
all.
Hope I have helped.
Alexandre Neto
--- On *Tue, 5/17/11, DB /<[email protected]>/* wrote:
From: DB <[email protected]> Subject: [Qgis-user] New starter on
QGIS & I need help!!!!! To: [email protected] Date: Tuesday,
May 17, 2011, 2:12 AM
Hi all,
I've just loaded Qgis under Fedora 14 to try and do some of the
things that happen in Oziexplorer. (I'm an official at a number of
Hot Air Balloon competitions where Ozi is currently used for
evaluating GPS tracks)
I've managed to get our (next)competition map loaded into qgis, but
haven't yet found a way to fix the scale of the map. It is a 50000
map which has been scanned to jpeg. We also have an ozi .map file
which would appear to my pretty much untrained eye to be the info
which identifies the UTM coordinate system in use on the map.
My first question to you guys is... how do I tell qgis to convert the
pixel(?) counts to UTM grid?
Hi Brent & Alexandre,
Thanks for your help.... B u t.. after a lot of playing with qgis &
Georeferencer, I'm still stuck!
I guess there must be a clarification hidden in a document "Somewhere
over the rainbow", but I have to confess, I can't find it - usual
problem of an otsider coming in & expecting everything to work
automatically, RTFM only to be done as a last step!
OK... so I started Georef, saw how the information got put out & made a
file containing the 9 UTM cross points as given in Ozi's .map file.
Restarted, danced 3 times round the maypole & eventually got my 9 points
to plot on the Georef mini-map & the QGIS big map - yippee! and in the
right places!! BUT I don't
seem to be able to tell anything what these 9 points represent.
In Ozi .map, I have
point01,xy,2412, 2380,in,deg, , ,N, , , W,grid,31,704000,5552000,N
point02..... etc. In Georef all I appear to be able to input is
2411.496,-2379.907 under SrcX & Y, which turns into
mapX,mapY,pixelX,pixelY,enable
2412.000000000000000,-2380.000000000000000,2412.909978693178800,-2382.054865056816197,1
in the GCP "points" file
Nowhere for the UTM 31 N 704000 5552000.
If I double click on any of the boxes in the table, I get sent of to a
transformation panel which might as well be written in hieroglyphs for
all I understand of it!
I selected
Transformation Type: Linear
Resampling method: Linear
Output raster: /home/Dave/Desktop/Luxgsm/map/trial_01
Target SRS: EPSG:32631
Set Target Resolution: on
Horizontal: 1.00000
Vertical: -1.00000
Load in QGIS when done: on
With this I get on the Georef window bottom panel:
Transform: Linear Translation (-0.326581, 0.800639) Scale (1.00004,
1.00008) Rotation: 0 Mean error 0.717116, followed by the current mouse
coordinates.
I guess (!) I'm quite a long way into my trial, but, like Hansel &
Gretel, I can't see wood for trees!!! I've tried the qgis "easy
guide", but it doesn't appear to go where I want; I tried the Georef
help.... At least I now know that a GCP is a Ground Control Point!
So, my plaintive voice in the wilderness(!!), can someone either give me
a cook-book sequence of How-tos to make Qgis recognise my UTM grid(s) or
point me to a Beginners Guide somewhere in I'net space????
BTW, I have to deal with 2 UTM bands 31N & 32N.
Many, many thanks for any help
Dave
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