Regarding the default values option/limitations, I can add that if
you try to use the default values expression dialog to build an
expression using geomintersects() the dialog will evaluate the
expression as invalid. Instead, build the expression in the field
calculator and then copy/paste it into default value box and skip
using the expression dialog.
Andrew
On Wed, Dec 21, 2016 at 1:32 PM, DelazJ <[email protected]
<mailto:[email protected]>> wrote:
Hi,
Laurent, I can think about different ways you can test to tackle
your issues, provided you have two spatial layers that overlap
(and without any intermediate layer creation):
- recent QGIS introduce default values concept
(http://docs.qgis.org/testing/en/docs/user_manual/working_with_vector/vector_properties.html#common-settings
<http://docs.qgis.org/testing/en/docs/user_manual/working_with_vector/vector_properties.html#common-settings>)
- i'm not really sure about its limitations though
- add a virtual field
(http://docs.qgis.org/2.14/en/docs/user_manual/working_with_vector/attribute_table.html#editing-attribute-values
<http://docs.qgis.org/2.14/en/docs/user_manual/working_with_vector/attribute_table.html#editing-attribute-values>)
that you could later recalculate into a simple field
- use the Autofields plugin
(http://plugins.qgis.org/plugins/AutoFields/
<http://plugins.qgis.org/plugins/AutoFields/>)
- use the SpatialJoin plugin
(http://plugins.qgis.org/plugins/spatialJoin/
<http://plugins.qgis.org/plugins/spatialJoin/>)
Except the SpatialJoin plugin option (which is internally based
on it), you'll need to write an expression likely based on
refFunctions plugin (e.g, geomintersects) someone mentioned above.
HTH,
Harrissou
2016-12-21 19:23 GMT+01:00 Laurent Bourlet
<[email protected] <mailto:[email protected]>>:
Hi,
i thought it was more easy ...
In fact , i don't use a GPS because these points don't need
precision : they are only used to identify the parcels . And
i would like to catch their identity ( a number for each
parcel and the owner ) if possible with a dynamic spatialjoin...
With booth data ( number of parcel and name of owner ) , i
could talk with the fisc administration :-)
Randy was right ...i didn't have the same EPSG for the two
layers . It's now OK ! but without the feature "dynamic" .
Indeed , i would avoid building many temporaries layers and i
thought it existed a plugin for this " dynamic" feature.
If no , i will ask my users to make spatialjoins some time to
time ...
Waiting , i will try the solution of Bernd...
Thank you anyway !
laurent
Le 21/12/2016 à 17:46, Bernd Vogelgesang a écrit :
Hi,
for me this sounds more like he is getting new points
once in a while and
wants to join those attributes to the new points
"automatically" from the
parcel layer.
The biggest problem for users is to rethink the workflow
from the end to
the beginning and to know the limitations.
The outcome should be a point layer with the polygons
attributes. If those
points (layer A) are from GPS as Randy assumes, they have
to be
reprojected to the parcels layer (layer B) before being
able to join them
spatially(layer C). The spatial join in the toolbox
produces layer D.
Most probably, the resulting layer D is going to to be
edited in some way
(adding notes about size, the progress, classifications,
whatever), so you
will have to find a way to preserve those new attribute
while being able to
add new points without much trouble.
The processing toolbox is a good way to do these steps,
though it produces
a lot of temporary files cluttering the project.
A better way for all those repetitive tasks, is to use
the graphical
modeller, to create a workflow which only has to be
triggered once new
points come in, and the resulting file can be saved as
new a file e.g.
with the current date in the name, so you have kind of an
archive and do not
overwrite previous files (and destroy your work in case
something goes
wrong).
So I can imagine a model with input layer A (new points
in WGS84 without attributes) and a parcel layer B (in
whatever projection).
reproject layer A and C will be created as an
intermediate step.
Next input layer is the latest result layer D,
reprojected and with attributes.
Merge layer C and D -> E. Now delete all columns which
are from layer B (from the last spatial join.
Unfortunately, you can only delete one field at a time in
the modeller, so you'll will have to add the command
several times in a row to the model) -> Fn
Do the spatial join of Fn with B.
The last result G will now hold all points with the
corresponding parcel info plus additional fields you
might have added to the points.
G will be the input D in the next run with fresh points.
So, do not add new points to the already existing
collection of points in WGS84 (it is never save to edit
layers without backup), but just import them as a new
input set and then run the model with the parcel layer
and the last result layer.
The modeller is not as intuitive as it should be, but it
can save you a lot of time once you managed to set up a
model.
Maybe I was completely wrong analysing the problem, but
maybe someone else has the problem that fits to my
solution ;)
Cheers
Bernd
Am 21.12.2016, 14:07 Uhr, schrieb Randal Hale
<[email protected]
<mailto:[email protected]>>:
2 things:
1. In QGIS there is a processing toolbox (I assume
you are one something as new as version 2.14.8). Open
it (it's at the top -> Processing -> Toolbox). You
can search for tools. Search for "join" and you
should see a "Join Attributes by location". This is a
spatial join.
2. THE MOST IMPORTANT THING. You mentioned you had
collected points with a GPS. Possibly these points
are in EPSG:4326. I'm going to guess that your parcel
layer isn't. If you right click your parcel layer (in
the layers panel) it will allow you to select
properties. On the General Tab you will see the
Coordinate Reference System mentioned and many times
it is something like EPSG:xxxx . A Spatial Join must
have the layers in the same coordinate system.
If it is different - Right Click on your GPS points
and "Save as". When the "Save vector layer as...."
window comes up. Save it as a shapefile and MOST
IMPORTANTLY change the CRS to match your parcel
layer. Click on the small globe (that appears to be
wearing a hat) and in the filter type in the number
you see for your parcels. You can then select that
projection and Save your file. It should save. You
can then perform the "join by location".
It should work. You are very close though so don't worry.
Randy
On 12/21/2016 01:24 AM, Erwan Conseil wrote:
Hi
In my layer B , I have the name of the owner and
the number of the parcel : this number , a
polygon , have a WKT location . All this is in a
SHP . As I grab points in layer A directly in
Qgis (2.18) , I have also a SHP . And i need a
dynamic join because I have no desire to make the
spatial join each time...
Regards
Laurent
Le 21 déc. 2016 à 01:30, Randal Hale
<[email protected]
<mailto:[email protected]>> a
écrit :
In your layer B - Do the Names of the Owners
have a location (like a tax parcel) or are
they a spreadsheet (like Microsoft Excel)?
Randy
On 12/20/2016 06:03 PM, Laurent Bourlet
wrote:
Hi at all
I'm a beginner in Qgis and i would make a
dynamic spatialjoin.
In fact , i have created a vector layer (
for example A) and i grab points in it
when I'm outdoor ( these points are
buildings unknowned by the government and
so these building are not taxed ...) . I
have also a layer (B) with the name of
the owners of these lands .
You see what i would ?...
I would have these names transferred as
attribut from B to A .
For that , i think about a spatialjoin
with a dynamic feature . So i have
downloaded the two plugins "reffunction"
and "spatialjoin".
But i have certainly maked something
wrong because i don't succeed ...
Is it the good method ?
And If yes , and if exist a doc about
these plugins ...i'll take it :-))
regards
Laurent
( pour les francophones ...je repère et
saisis des points représentants des
batiments construits et visibles par
Google Map mais inconnus par le cadastre
et donc les impôts ...je voudrais donc
enrichir la couche de saisie par les
références des parcelles et les noms des
propriétaires par une jointure spatiale
dynamique ..à chaque point saisi ,
"monte" cette référence )
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North River Geographic Systems, Inc
http://www.northrivergeographic.com
<http://www.northrivergeographic.com>
423.653.3611 [email protected]
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