So I'm in the process of developing a web application, I am using open source tools so qgis, postgis, play framework for the web app. And I have come across an interesting problem that I'm trying to work on if someone might be able to point me in the right direction.

What I need to do is this I have one polygon layer A with attributes about the polygons, and polygon layer B with attributes also.

So if a polygon in layer B falls within a polygon in layer A look up the attributes for the polygon in A, now compare those with the attributes of the polygon in layer B to determine if the attribute for the polygon in B is a multiple ( 2x, 3x, 4x, etc ) of the attribute of the polygon in A.

I am going to be using the results of this in the web application for other things.

So I have multiple options, but looking for some direction as to where to start. Do I need to use something like sextante? There are several of these operations that I need to do. It Should be repeatable, but only need to be repeated when updates to the layers come out 1 or twice a year! But it will be acting on several states data layers.

Thank you in advance for any help that you all may bring. Thank you PolyGeo for suggesting to edit the post

  • What software are you using? – Dan_h_b Jan 16 '14 at 14:53
  • You can use the edit button beneath your Question to revise it with this additional information. – PolyGeo Jan 16 '14 at 20:02

Take a look at this demo that Paul Ramsey at Boundless posted:


The key here is linking a PostGIS "parametric" SQL view to a web client. The tools in this particular example seem to be PostGIS, GeoServer, and OpenLayers... I think a little Boostrap in there for the framework of the page. You could likely use Leaflet instead of OpenLayers, though I haven't seen an example of that.

In your case, you're using a ST_Intersect function in PostGIS to link the two datasets, and that published to GeoServer can be accessed through the OpenLayers web component

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