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I have a very large .gml file with multiple layers in it. I would like to export one of these layers to .shp. It is a polygon layer (of lakes). However, I am getting the error:

ERROR 1: Unrecognised geometry type <Surface>.

The ogr command I was using:

ogr2ogr -f "ESRI Shapefile" output.shp input.gml layername

Any thoughts? Is it possible the polygon layer is somehow incorrectly defined as a surface in the GML? Any way I can force it to be a polygon? Or is it something else entirely? I don't often work with .gml, so may be missing something obvious...

EDIT 20101202: Here is a snip of (what appears to be) the relevant info from an example feature in the example file linked below: <gml:featureMember>
<gml:surfaceProperty>
<gml:Surface srsName="EPSG:4140" srsDimension="2">
<gml:patches>
<gml:PolygonPatch>
<gml:exterior>
<gml:LinearRing>
<gml:posList>52.2023177 -77.596532 52.2024007 -77.5963559 52.2028141 -77.5962899 52.2028362 -77.5964181 52.2026119 -77.5967049 52.2024106 -77.5967968 52.2023273 -77.5966966 52.2023177 -77.596532</gml:posList>
</gml:LinearRing>
</gml:exterior>
</gml:PolygonPatch>
</gml:patches>
</gml:Surface>
</gml:surfaceProperty>

So, the file is identifying it as a 'surface' as well as a 'PolygonPatch'? Perhaps the question should be: what is a 'surface' in a .gml file?

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What is the output of "ogrinfo input.gml -ro -al"? –  geographika Nov 29 '10 at 14:36
    
ogrinfo gives the same "ERROR 1: Unrecognised geometry type <Surface>." –  Darren Cope Nov 29 '10 at 15:18
    
Are you using the latest version of GDAL/OGR? gdal.org/ogr/drv_gml.html –  geographika Nov 29 '10 at 15:32
    
I am using 1.7.0b2 –  Darren Cope Nov 29 '10 at 16:44
    
Can you post a sample of the GML or a link to the file? –  DavidF Nov 30 '10 at 15:17
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2 Answers

You need to use GDAL 1.8.0 or above to be able to read this kind of GML3 geometry.

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if somebody knows, that's you Even :) –  Ragi Yaser Burhum Jun 25 '11 at 19:34
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Looks like you have GML3 but ogr2ogr is expecting it to be GML2. According to the docs (http://www.gdal.org/ogr/drv_gml.html) only GML 2 or GML 3 Simple Feature is supported, since GML3 SF doesn't support surfaces either I'd say you are out of luck.

I'm also not entirely sure if a shapefile can support surfaces either so I suspect that you are going to run into problems with any solution trying to go this way.

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The issue is that the feature should be a polygon, according to all of the documentation I can find. It appears that OGR is identifying it incorrectly as a surface when it shouldn't. –  Darren Cope Nov 30 '10 at 12:59
1  
It seems more likely that the documentation of your data is wrong than OGR is misreading "polygon" as "surface" but a quick grep of the data file should solve the issue. –  iant Nov 30 '10 at 16:15
    
I have pasted a snippit into the original question. –  Darren Cope Dec 2 '10 at 16:18
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