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I'm trying to convert multipolygon to in the right-hand format so that Leaflet can use it on the front end.

ogr2ogr -nln [target_table] -nlt PROMOTE_TO_MULTI -lco GEOMETRY_NAME=geom -lco FID=gid -lco RFC7946=YES -lco PRECISION=NO Pg:"dbname=[taget_db] host=localhost user=spatial_user port=5432" source_sub_counties.shp

Import is done but there is warning:

Warning 6: dataset Pg:dbname=[target_db} host=localhost user=spatial_user port=5432 does not support layer creation option RFC7946

How to fix this issue ?

Versions:

  • GDAL 3.4.1, released 2021/12/27
  • PostgresSQL version 14
  • Ubuntu Linux 22/04
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The RFC7946=[YES/NO] option is a layer creation option of the GeoJSON driver https://gdal.org/drivers/vector/geojson.html. Other drivers do not have that creation option, including the PostGIS driver https://gdal.org/drivers/vector/pg.html.

In PostGIS the orientation of the rings can be controlled with the functions https://postgis.net/docs/ST_ForcePolygonCCW.html and https://postgis.net/docs/ST_ForcePolygonCW.html. The "CCW" stands for counter-clockwise orientation of the exterior ring, and "CW" stands for clockwise orientation of the exterior ring.

Please clarify how do you plan to use the PostGIS data in Leaflet.

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  • pool.query("SELECT id, ST_AsGeojson(geom)::json as polygon, name FROM public.table_name");
    – matsukan
    Commented Feb 19 at 15:16
  • Frontend side : {subcounties && (<GeoJSON key='my-geojson' data={subcounties} style={styles} attribution='counties' />)}
    – matsukan
    Commented Feb 19 at 15:18
  • All this happens after ogr2ogr has done its job. See postgis.net/docs/ST_AsGeoJSON.html about the PostGIS side, including the hint about using ST_ForcePolygonCCW if needed.
    – user30184
    Commented Feb 19 at 15:42

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