[GIS] ny efficient way to convert GeoJSON to WKT

convertgeojsonpostgiswell-known-text

I want to use ST_GeomFromText() to load vector data to PostGIS. However, I don't know how to convert from Geojson type to WKT.

N.B. I know I can use OGR2OGR to upload the GeoJSON directly, but I just want to confirm if there is any way to convert it or not.

Best Answer

why not use

ST_GeomFromGeoJSON which takes as input a geojson representation of a geometry and outputs a PostGIS geometry object.
ST_AsGeoJSON, the inverse

see Creating GeoJSON Feature Collections with JSON and PostGIS functions or ST_GeomFromGeoJSON from OpenGeo.

To convert to WKT, use

ST_AsText , the reverse of ST_GeomFromText() which return the Well-Known Text (WKT)
ST_AsEWKT same with SRID meta data

Related Solutions

Convert Shapefile – How to Convert Shapefile to WKT (Well-Known Text)

Well Known Text is not meant for saving layers like shape files that consists of many objects. WKT defines how to represent geometry of one object. That geometry could be single or multi part. Multi part geometries mean that geometry of one object consists of many parts. For example Hawaiian Islands could be represented as one object but it consists of many geometries.

Shape file is a collection of these kinds of objects. Objects usually have also some attribute information that is also part of a shape file.

Your ogr2ogr approach converts these objects to csv format with WKT geometry (and text representations of the attributes). If you really want to combine all the geometries to one MULTIPOLYGON you have to first convert all the objects to one multi geometry. You can do that in QGIS. Select from Vector menu Geometry Tools and then Singleparts to Multiparts. Then you can convert that to wkt with ogr2ogr.

Hopefully this makes sense.

OpenLayers GeoJSON – Converting GeoJSON to WKT with OpenLayers2

Not sure what you mean by "it's not working", I'm getting output that looks correct:

var val = ''; // your GeoJSON goes here
var wkt_options = {};
var geojson_format = new OpenLayers.Format.GeoJSON();
var testFeature = geojson_format.read(val);
var wkt = new OpenLayers.Format.WKT(wkt_options);
var out = wkt.write(testFeature);

alert(out);

See it in action: http://jsfiddle.net/FUeJj/

Best Answer

Related Solutions

Convert Shapefile – How to Convert Shapefile to WKT (Well-Known Text)

OpenLayers GeoJSON – Converting GeoJSON to WKT with OpenLayers2

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