[FWTools] which tool to replace ArcGIS feature to polygon function

Frank Warmerdam warmerdam at pobox.com
Thu Oct 9 09:55:45 EDT 2008


Stefan Muthers wrote:
> Hello,
> 
> sorry, I do not know where to post this question. Since fwtools include 
> many free software GIS tools, maybe someone could help me.
> 
> I have polylines I want to convert to polygons. Each polygon has an 
> attribute that is taken from a point object located in the polygon area.
> 
> Until now, I use ArcGIS feature to polygon function, which works quite 
> well. Due the rest of the processing is automated and realised with free 
> software I would like to replace this step.
> 
> Is there any free software tool with the functionality of the ArcGIS 
> tool? The best think would be a python function.

Stefan,

I am not aware of a clean way of doing this with GDAL/OGR or anything else
in FWTools.  It is possible with scripting but then it is rather involved.

One script that might be of interest is the assemblepoly.py script which
collects edges of a polygon from a topological datasource (TIGER in this
case I think) and assembles them into polygons.  In theory these could
then be used for a spatial query on a point layer to find the contained
point.

http://trac.osgeo.org/gdal/browser/trunk/gdal/swig/python/samples/assemblepoly.py

But I suspect you would be better looking at packages like GRASS, or
gvSIG that aspire to more complete GIS functionality.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | Geospatial Programmer for Rent



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