On 10/13/05, Martin Tomko <[EMAIL PROTECTED]> wrote: > I am desperately seeking a tool/workflow o export vector data into > text/tables with basically the arc/node topological description of my data. > > So If I export polygons, I need a table with the polygon IS and the IDs > of all its arcs, without any coordinates. Does anyone know a way? > > I was thinking about postgress/postgis? Dump a shp in it and try an sql? > Would ogr2ogr do it somehow? I did not find a way to include the IDs of > the arcs of a polygon. Seems like export to CSV would help, but I need > to get the arcs IDs somehow.
Martin, You didn't mention what data you are starting with. Is it a shapefile? If so, part of your problems is that you need to build the topology from a non-topological structure. As Flavio mentioned, FME would be a good choice for that. GRASS also has support for converting non-topological dataset to topological. If you are already starting with a topological Arc/Info binary vector coverage, then you will see from the ogrinfo reports that the topology information is available as attributes. OGRFeature(PAL):2 ArcIds (IntegerList) = (1:-349) AREA (Real) = 0.92814 PERIMETER (Real) = 5.35872 COUNTRYD# (Integer) = 2 COUNTRYD-ID (Integer) = 3027 POLYGON ((-153.022781372070312 57.383213043212891,... OGRFeature(ARC):1 UserId (Integer) = 1394 FNODE# (Integer) = 1 TNODE# (Integer) = 2 LPOLY# (Integer) = 24 RPOLY# (Integer) = 26 LINESTRING (56.360397338867188 25.983451843261719,... The ArcIds on the polygons and the node/poly information on the arcs is enough to establish the topological relationships. With a script or C++ program written on OGR you could get that information out into a text format of some kind. If you use GRASS to export to E00 you could use avcimport to convert to a binary coverage for use with OGR. FME can write binary coverages directly. Of course, both FME and GRASS offer other mechanisms to interact with the topology that might be more direct. Best regards, -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, [EMAIL PROTECTED] light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | Geospatial Programmer for Rent
