Constructing WKT POINT from GeoJSON data fields in OGR

Question

Let's say I have:

$ ogrinfo ...
OGRFeature(SELECT):0
  name (Integer) = 29670000
  lon (Real) = 120.870582715925
  lat (Real) = 24.183864790114

How do I get an additional:

POINT (120.870582715925 24.183864790114)

And this is my command:

$ ogrinfo qingfujie_roads.geojson -dialect SQLite -sql \
'SELECT land_id AS name, xcenter AS lon, ycenter AS lat FROM "qingfujie_roads"'

Answer 1

Given my dummy data:

$ cat qingfujie_roads.geojson
{
    "type": "FeatureCollection",
    "name": "qingfujie_roads",
    "features": [
        { "type": "Feature", "properties": { "land_id": "123", "xcenter": 120.870582715925, "ycenter": 24.183864790114}}
    ]
}

Output in one go using OGR Spatialite SQL functions ST_Point (create point geometry from x,y) and ST_AsText (create the WKT from geometry):

$ ogr2ogr -f CSV /vsistdout/ qingfujie_roads.geojson -dialect SQLite \
  -sql 'SELECT land_id AS name, ST_AsText(ST_Point(xcenter, ycenter)) as WKT FROM "qingfujie_roads"'
name,WKT
"123",POINT(120.870583 24.183865)

Or

$ ogrinfo qingfujie_roads.geojson -dialect SQLite \
  -sql 'SELECT land_id AS name, ST_AsText(ST_Point(xcenter, ycenter)) as WKT FROM "qingfujie_roads"'
INFO: Open of `qingfujie_roads.geojson'
      using driver `GeoJSON' successful.

Layer name: SELECT
Geometry: None
Feature Count: 1
Layer SRS WKT:
(unknown)
name: String (0.0)
WKT: String (0.0)
OGRFeature(SELECT):0
  name (String) = 123
  WKT (String) = POINT(120.870583 24.183865)

Documentation on OGR SQL if built with spatialite support:

• OGR Spatialite SQL functions
• Spatialite topics

Answer 2

Alas,
https://gdal.org/en/latest/drivers/vector/geojson.html
doesn't say what to do. Yes one surely could do it in one step, but how to has never been documented.

However
https://gdal.org/en/latest/drivers/vector/csv.html#reading-csv-containing-spatial-information
certainly does say what to do. Therefore consider converting your GeoJSON into CSV first. Let's try that two step approach:

Step 1:

$ ogr2ogr qingfujie_roads.csv qingfujie_roads.geojson -dialect SQLite -sql \
'SELECT land_id AS name, xcenter AS lon, ycenter AS lat FROM "qingfujie_roads"'
$ cat qingfujie_roads.csv
name,lon,lat
29670000,120.870582715925,24.183864790114
29680000,120.870047099875,24.183650358631
...

Step 2:

$ ogrinfo -ro -al qingfujie_roads.csv -oo KEEP_GEOM_COLUMNS=NO \
-oo X_POSSIBLE_NAMES=lon -oo Y_POSSIBLE_NAMES=lat

Layer name: qingfujie_roads
OGRFeature(qingfujie_roads):1
  name (String) = 29670000
  POINT (120.870582715925 24.183864790114)