Create a Feature Collection from Postgis Geometries using Postgis >= 3.0.0

sijakubo@gmail.com ( Simon Jakubowski) — Thu, 27 Apr 2023 00:00:00 +0000

Generating a Feature and Feature Collection form postgis is rather simple. If you convert a simple GEOMETRY with the st_asgeojson postgis will generate a GeoJSON “geometry”.

SELECT st_asgeojson(f.geometry)
FROM field f;

will result in a single geometry:

{
  "type" : "Polygon",
  "coordinates" : [...]
}

If you provide a RECORD (since Postgis 3.0.0), postgis will generate a Feature with all the fields as Properties:

SELECT st_asgeojson(f.*)
FROM field f;

will result in:

{
  "type" : "Feature",
  "geometry" : {
    "type" : "Polygon",
    "coordinates" : [
      ...
    ]
  },
  "properties" : {
    "id" : "052ff36a-4ea7-4307-9bc3-414f49a62163",
    "area_square_meters" : 29434,
    "altitude" : 40,
    "granule_code" : "31UGT",
    "creation_date" : "2021-10-21T23:32:25.974059",
    "name" : "Simple test field",
    ...
  }
}

Where the field table having the Columns: id, area_square_meters, …

Feature - Tag - Simon Jakubowski

Create a Feature Collection from Postgis Geometries using Postgis >= 3.0.0