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

Stefan Muthers stefan.muthers at zamg.ac.at
Wed Oct 15 06:17:19 EDT 2008


Frank Warmerdam schrieb:
> 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.
> 
> 
> 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 
> 

thanks, but I have no attribute like 'TILE_REF' that connects the lines 
of a polygon.

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

yes, thank you. I will try that.

regards
   stefan



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