[Qgis-user] Spatial Join

[Randal Hale]

Let me get to a good stopping point this morning and I'll test something 
out. I think I might be able to say yes to the tool. I think.


-----------------
Randal Hale, GISP
North River Geographic Systems, Inc
http://www.northrivergeographic.com
423.653.3611 rjhale at northrivergeographic.com
<mailto:rjhale at northrivergeographic.com>
twitter:rjhale
http://about.me/rjhale

On 08/08/2013 08:20 AM, Jonathan Moules wrote:
> Hi Randal,
> I had noticed the polygons to points converter, but wanted to do it 
> "properly" - i.e. with a polygons in polygons comparison.
>
> Your method will likely work but adds two extra steps (conversion to 
> points and then from points back to polygons). Does QGIS not have a 
> tool for this then?
>
> Thanks!
>
> Jonathan
>
>
> On 8 August 2013 13:12, Randal Hale <rjhale at northrivergeographic.com 
> <mailto:rjhale at northrivergeographic.com>> wrote:
>
>     Here's how I would do it: You have Two polygon layers and you need
>     to count the number of polygons in layer 1 that are contained in
>     the polygons in layer 2
>
>     1. Convert the polygons in 1 to points: Vector -> geometry ->
>     polygon centroids
>     2. then use -> vector -> analysis tools -> points in polygon.
>     Count the number of points contained by polygons in layer 2.
>
>     Hope that helps or at least creates an idea.
>     Randy
>
>     -----------------
>     Randal Hale, GISP
>     North River Geographic Systems, Inc
>     http://www.northrivergeographic.com
>     423.653.3611  <tel:423.653.3611>  rjhale at northrivergeographic.com  <mailto:rjhale at northrivergeographic.com>
>     <mailto:rjhale at northrivergeographic.com>  <mailto:rjhale at northrivergeographic.com>
>     twitter:rjhale
>     http://about.me/rjhale
>
>     On 08/08/2013 07:36 AM, Jonathan Moules wrote:
>>     Hi List,
>>        I have two layers of polygons. I want to do some analysis
>>     between them, basically doing a spatial join, counting how many
>>     of one polygon layer there are intersecting with each polygon in
>>     the other layer.
>>     ArcGIS does this easily with the "Spatial Join" tool (ArcToolbox
>>     version). How can I do this in QGIS?
>>
>>     I know there is Vector -> Data Manage Tools -> Join attributes by
>>     location, but that only acts as a basic join and doesn't allow
>>     for counting of the number of joins.
>>
>>     Sextante has a large collection of tools, but none of them seem
>>     to have any help so I don't know what any of them do. (And none
>>     of them seem applicable anyway).
>>
>>     Suggestions welcome, Cheers,
>>     Jonathan
>>
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>
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