2

Right now I have a GeoJson file with a structure like this:

{
"geometry": {
    "type": "MultiLineString",
    "coordinates": [
        [  <Coords line 1>
        ],
        [  <Coords line 2>
        ],
        [  <Coords line 3>
        ] 
    ]
},
"type": "Feature",
"properties": {
    "time": 960,
    "value": 0.5
} }

I want to create a MultiPolygon shapefile from that but ogr2ogr throws an error using this command:

ogr2ogr -f "ESRI Shapefile" -nlt MULTIPOLYGON <out_file.shp> <file.shp> OGRGeoJson


ERROR 1: Attempt to write non-polygon (MULTILINESTRING) geometry to POLYGON type shapefile.

I've been searching other possibilities to achieves this and for example with QGis is quite simple, but I need a solution that can be used from terminal.

As a side note, all the lines in the geoJson starts and ends at the same point, so they make a closed line.

0

Use the SQLite/SpatiaLite SQL dialect http://www.gdal.org/ogr_sql_sqlite.html and you can utilize all that is supported by SpatiaLite http://www.gaia-gis.it/gaia-sins/spatialite-sql-latest.html.

Test with ogrinfo

ogrinfo -dialect sqlite -sql "select BuildArea(geometry) from multiline" multiline.json
INFO: Open of `multiline.json'
      using driver `GeoJSON' successful.

Layer name: SELECT
Geometry: Unknown (any)
Feature Count: 1
Extent: (0.000000, 20.000000) - (20.000000, 40.000000)
Layer SRS WKT:
GEOGCS["WGS 84",
    DATUM["WGS_1984",
        SPHEROID["WGS 84",6378137,298.257223563,
            AUTHORITY["EPSG","7030"]],
        AUTHORITY["EPSG","6326"]],
    PRIMEM["Greenwich",0,
        AUTHORITY["EPSG","8901"]],
    UNIT["degree",0.0174532925199433,
        AUTHORITY["EPSG","9122"]],
    AUTHORITY["EPSG","4326"]]
Geometry Column = BuildArea(geometry)
OGRFeature(SELECT):0
  POLYGON ((0 20,0 40,20 40,20 20,0 20))

And then convert with ogr2ogr. I left out the -nlt multipolygon because in shapefiles polygons and multipolygons are the same.

ogr2ogr -f "ESRI Shapefile" -dialect sqlite -sql "select ST_BuildArea(geometry) from multiline" out.shp multiline.json

It gets boring to write answers about all that is possible to do with ogrinfo, ogr2ogr, and SQLite dialect. There have already quite many https://gis.stackexchange.com/search?q=dialect+sqlite. Do we have FAQ?

  • Thanks, I'll try to test this solution. But now I have to update the gdal version I'm using since it does not support -dialect sqlite (GDAL 1.9.0, released 2011/12/29) – Cristhian Rivera Feb 13 '18 at 15:22

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