[gdal-dev] ogr2ogr -nlt PROMOTE_TO_MULTI (use case: converting shapefiles to PostGIS)
even.rouault at mines-paris.org
Wed Sep 26 14:37:39 PDT 2012
Have you ever been frustrated about shapefiles mixing polygons/multipolygons
(or linestrings/multilinestrings) in the same layer and issues when converting
them to PostGIS ?
I was, until a few minutes ago, where I've just added in GDAL trunk "-nlt
PROMOTE_TO_MULTI" as an accepted option of ogr2ogr.
The effect of this option is that when a layer is of type Polygon, it will be
converted in the target format as MultiPolygon, and any Polygon feature in the
layer will be promoted to MultiPolygon (existing MultiPolygons will be left
untouched). The same for LineString / MultiLineString. Other geometry types
will be left untouched (i.e. Point will not be converted to MultiPoint (they
are identified as separate types in shapefiles).
This option works for any source or target datasource, so the shapefile ->
PostGIS is just one particular (but typical) use case.
Previously you could use -nlt MULTIPOLYGON or -nlt MULTILINESTRING but that
couldn't be used when doing a mass conversion of shapefiles that mixed different
types of geometries.
More information about the gdal-dev