[gdal-dev] ogr2ogr and GPX files

Dylan Beaudette dylan.beaudette at gmail.com
Mon Mar 3 19:59:48 EST 2008


On Monday 03 March 2008, Even Rouault wrote:
> In fact, using the same principle, you can use just one command line and no
> intermediary file :
>
> ogr2ogr -f GPX destination.gpx source.shp -sql "SELECT  src_field_1 AS
> name, src_field_2 AS desc FROM your_source_layer_name"
>
> Thanks to FrankW for the tip ;-)

Thanks Even / Frank.

One small problem:


ogr2ogr -t_srs '+proj=latlong +datum=WGS84' \
-f GPX -dsco GPX_USE_EXTENSIONS=YES \
veg_points.gpx veg_points.shp \
-sql "SELECT cat AS foo FROM veg_points"

ERROR 1: SQL: Missing comma after column cat in SELECT statement.

Could this be a bug or my version of GDAL too old ? This is with GDAL SVN, 
checked out a couple of weeks ago.

I get a valid GPX file if I do not use the "AS foo" operator.

Ideas?

Dylan



> Le Monday 03 March 2008 19:43:12 Even Rouault, vous avez écrit :
> > Hi,
> >
> > I see your point...
> >
> > The solution is the powerful OGR Virtual Dataset format !
> > See http://www.gdal.org/ogr/drv_vrt.html
> >
> > In fact, the documentation should probably be extended to demonstrate the
> > power of the OGR SQL for that particular case
> >
> > Try to paste the following lines in a file (remapped_layer.vrt would be
> > fine)
> >
> > <OGRVRTDataSource>
> >     <OGRVRTLayer name="remapped_layer">
> >         <SrcDataSource>your_source.shp</SrcDataSource>
> >         <SrcSQL>SELECT src_field_1 AS name, src_field_2 AS desc FROM
> > your_source_layer_name</SrcSQL>
> >     </OGRVRTLayer>
> > </OGRVRTDataSource>
> >
> > Replace your_source.shp, src_field_1, src_field_2 and
> > your_source_layer_name by the appropriate values from your source dataset
> > and 'ogrinfo -ro -al remapped_layer.vrt' should show a structure
> > compatible of a GPX file.
> >
> > Best regards,
> > Even
> >
> > Le Monday 03 March 2008 07:04:41 Dylan Beaudette, vous avez écrit :
> > > Hi,
> > >
> > > is there a simple approach (via ogr2ogr) to create GPS files which have
> > > standard waypoint tags such as <name>, <elev>, <cmt>, etc. by
> > > re-mapping columns in the attribute table of the source vector?
> > >
> > > for example:
> > >
> > > # export points vector from GRASS
> > > v.out.ogr in=wp type=point dsn=wp.shp
> > >
> > > # convert tp GPX:
> > > ogr2ogr -t_srs '+proj=latlong +datum=WGS84' \
> > > -f GPX -dsco GPX_USE_EXTENSIONS=YES \
> > > wp_gps.gpx wp.shp
> > >
> > > This results in a working GPX waypoints file, that when uploaded to a
> > > GPS is functional, but the waypoints are all re-named sequentially.
> > > Note that I am uploading the GPX file the GPS via gpsbabel.
> > >
> > > Does anyone know of the appropriate incantation that one could use to
> > > translate the column structure of the input wp.shp (i.e. the stuff in
> > > its .dbf) into standard waypoint tags?
> > >
> > > thanks in advance!
> > >
> > > PS: trying to write a simple tutorial for some colleagues [1]
> > >
> > > 1. http://casoilresource.lawr.ucdavis.edu/drupal/node/553
> >
> > _______________________________________________
> > gdal-dev mailing list
> > gdal-dev at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/gdal-dev



-- 
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341


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