[Qgis-user] spatialjoin
DelazJ
delazj at gmail.com
Thu Dec 22 06:17:21 PST 2016
Hi Randal,
You need refFunctions plugin installed
H.
Le jeudi 22 décembre 2016, Randal Hale <rjhale at northrivergeographic.com> a
écrit :
> Congrats - sorry I was almost leading own a more labor intensive path.
>
> So now I have a question? I'm on QGIS 2.18 on Linux - Where is
geomintersects()? I don't see it in Field calculator as something I can
use (I have a lot of geom functions) but just not that currently. I was
reading back through all the emails and maybe I'm missing something (I
haven't tried my windows version yet).
>
> Thanks in Advance,
>
> Randy
>
>
> On 12/22/2016 03:26 AM, Laurent Bourlet wrote:
>
> Hi at all
>
> i succeed !! thank's at all ...Andrew was right ... but i add an another
thing ; i have indicated in the dialogue box , under "default value" , in
"relational value" the name of the layer B , the right field etc... and now
it's ok !
>
> one more time , thank's !!
>
> laurent
>
> Le 21/12/2016 à 23:32, Andrew a écrit :
>
> 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 <delazj at gmail.com> 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)
- 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)
that you could later recalculate into a simple field
>> - use the Autofields plugin (http://plugins.qgis.org/plugins/AutoFields/)
>> - use the SpatialJoin plugin (
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 <laurentbourlet34 at gmail.com>:
>>>
>>> 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
>>>> <rjhale at northrivergeographic.com>:
>>>>
>>>>> 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 <
rjhale at northrivergeographic.com> 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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>>>>>>>
>>>>>>> -- -----------------
>>>>>>> Randal Hale
>>>>>>> North River Geographic Systems, Inc
>>>>>>> http://www.northrivergeographic.com
>>>>>>> 423.653.3611 rjhale at northrivergeographic.com
>>>>>>> twitter:rjhale
>>>>>>>
>>>>>>> _______________________________________________
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>>>>
>>>>
>>>
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> --
> -----------------
> Randal Hale
> North River Geographic Systems, Inc
> http://www.northrivergeographic.com
> 423.653.3611 rjhale at northrivergeographic.com
> twitter:rjhale
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