GeoJSON driver detects type on first feature

[barryrowlingson]

Numbers in OGR can be Integer or Real. If the numeric property of the first feature in a GeoJSON file looks like an Integer, then OGR treats that property as Integer, and numerically truncates any Real values in further features.

Example snippet of two features:

 { "type": "Feature", "properties": { "z1": 4, "z2": 2.100000 } [...]
 { "type": "Feature", "properties": { "z1": 3.2, "z2": 3.100000 } [...]

like that, ogrinfo reports

z1: Integer (0.0)
z2: Real (0.0)

and then drops .2 from 3.2 in the second feature:

OGRFeature(OGRGeoJSON):1
  z1 (Integer) = 3
  z2 (Real) = 3.1
  POINT (2 2)

Changing the first feature to:

{ "type": "Feature", "properties": { "z1": 4.0, "z2": 2.100000 }

(ie adding the ".0" to the "4") causes both fields to be Real.

The JSON spec only has 'number' class, and no differential between integers and reals, so maybe anything numeric should be an OGR Real.

[This was spotted in some GeoJSON generated by Geoserver]

[Even Rouault]

r22357 /trunk/gdal/ogr/ogrsf_frmts/geojson/ogrgeojsonreader.cpp: GeoJSON: better detection of OGR type for numeric JSON fields ( #4082 )

Will backport in 1.8 branch later

[Even Rouault]

r22358 /branches/1.8/gdal/ogr/ogrsf_frmts/geojson/ogrgeojsonreader.cpp: GeoJSON: better detection of OGR type for numeric JSON fields (#4082)