I am 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.

closed as too broad by PolyGeo Jul 7 at 13:11

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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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