[gdal-dev] Zonal statistics with GDAL/StarSpan

[Greg Ederer]

Brent,

My Google search didn't turn up much of use (most of the results were 
PostGIS-specific).  Do you know of a tool that would tell me which 
feature(s) have problems?  Do you know of a tool that might be able to 
fix these polygons?

Thanks!

Greg

Brent Fraser wrote:
> Greg,
>
>  It means the GEOS topology library is having problems with geometry 
> of your input shapefile.  Most likely related to duplicate vertices 
> (or near-duplicate) in a polygon.  Do a Google for "side location 
> conflict".   It would be nice if it spat out the FID of the offending 
> polygon...
>
> Brent
> Greg Ederer wrote:
>> Hi Brent,
>>
>> Thanks for the example.  Here's what I got:
>>
>> Macintosh-4:starspan_tests gregederer$ starspan2 --progress --RID 
>> none --vector 
>> /Users/gregederer/servers/geoserver_data/data/shapefiles/Admin/afadmn2n.shp  
>> --raster rfe_2006_04_pct.tif --stats  results.txt avg
>> starspan: --out-prefix: ?
>> Type `starspan --help' for help
>>
>> I then added a --out-prefix, like so:
>>
>> Macintosh-4:starspan_tests gregederer$ starspan2 --progress --RID 
>> none --vector 
>> /Users/gregederer/servers/geoserver_data/data/shapefiles/Admin/afadmn2n.shp  
>> --raster rfe_2006_04_pct.tif --stats  results.txt avg --out-prefix bar
>> starspan: --out-type: ?
>> Type `starspan --help' for help
>>
>> I then added '--out-type table' (I found in the source that valid 
>> --out-types are: table, mini_raster_strip, mini_rasters, rasterization):
>>
>> Macintosh-4:starspan_tests gregederer$ starspan2 --progress --RID 
>> none --vector 
>> /Users/gregederer/servers/geoserver_data/data/shapefiles/Admin/afadmn2n.shp  
>> --raster rfe_2006_04_pct.tif --stats  results.txt avg --out-prefix 
>> bar --out-type table
>> Number of features: 550
>> starspan_csv:   1: Extracting from rfe_2006_04_pct.tif
>>        0% terminate called after throwing an instance of 
>> 'geos::util::TopologyException'
>>  what():  TopologyException: side location conflict -8.25 23.1536
>> Abort trap
>>
>> Any idea what the TopologyException indicates?
>>
>> Thanks!
>>
>> Greg
>>
>> Brent Fraser wrote:
>>> Greg,
>>>
>>>  I've used StarSpan to do similar things; in my case I wanted "mode" 
>>> not "avg".  Using v1.2.01 (I don't think I made major mods to the 
>>> source):
>>>
>>>     starspan2.exe --progress --RID none --vector boundaries.shp  
>>> --raster big.tif --stats  results.txt mode
>>>
>>> I edited the resulting results.txt text (csv) file and used GDAL's 
>>> ogr2ogr to do a join on the shapefile's DBF file based on the FID.
>>>
>>> Brent Fraser
>>>
>>>
>>> Greg Ederer wrote:
>>>> Hello all,
>>>>
>>>> I'm a GDAL newbie.  I have a shape file containing subnational 
>>>> boundaries for Africa.  I have a raster containing rainfall for 
>>>> Africa.  I need to pull out the spatial average of rainfall for 
>>>> each of the subnational units.
>>>>
>>>> I think that I might be able to pull this off using StarSpan.  But, 
>>>> the docs on the StarSpan wiki do not line up with the current 
>>>> version of the program (the changelog mentions that certain command 
>>>> line switches have been eliminated, and others added; but it 
>>>> doesn't say what the new switches do, or how to use them).  I am 
>>>> digging through the StarSpan sources to try to figure out how to 
>>>> use it.
>>>>
>>>> Does anyone have any suggestions as to how I might get the needed 
>>>> data using GDAL (with, or without StarSpan)?
>>>>
>>>> Thanks!
>>>>
>>>> Greg
>>>>
>>
>>


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| E R G O N O S I S
| Greg Ederer
| Lead Developer
| greg at ergonosis.com
| 360.774.6848
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