[postgis-tickets] [PostGIS] #4799: ST_AsGeoJSON doesn't export the CRS of multiple geometry columns

[PostGIS]

#4799: ST_AsGeoJSON doesn't export the CRS of multiple geometry columns
----------------------------------+---------------------------
 Reporter:  tobwen                |      Owner:  pramsey
     Type:  enhancement           |     Status:  new
 Priority:  medium                |  Milestone:  PostGIS 3.1.0
Component:  postgis               |    Version:  master
 Keywords:  geojson, json, jsonb  |
----------------------------------+---------------------------
 == summary
 ST_AsGeoJSON only uses the first geometry column to create the feature's
 geometry. The other geometry columns get stored in properties. But here,
 the CRS is missing. It's not in GeoJSON specs, but it might be useful to
 reconstruct the geometry.

 == example
 {{{
 SELECT
     ST_AsGeoJSON(data.*)
 FROM
     (SELECT
         1 AS id,
         ST_Transform(geom, 3035) geom,
         ST_Transform(geom, 25832) geom
     FROM
         ST_SetSRID(ST_MakePoint(7, 51), 4326) geom
     ) data;
 }}}

 == result
 {{{
 {
   "type":"Feature",
   "geometry":{
     "type":"Point",
     "crs":{
       "type":"name",
       "properties":{
         "name":"EPSG:3035"
       }
     },
     "coordinates":[
       4110471.051819585,
       3103060.820290524
     ]
   },
   "properties":{
     "id":1,
     "geom":{
       "type":"Point",
       "coordinates":[
         359666.70366028673,
         5651728.682548149
       ]
     }
   }
 }
 }}}

 == nice to have
 {{{
 {
   "type":"Feature",
   "geometry":{
     "type":"Point",
     "crs":{
       "type":"name",
       "properties":{
         "name":"EPSG:3035"
       }
     },
     "coordinates":[
       4110471.051819585,
       3103060.820290524
     ]
   },
   "properties":{
     "id":1,
     "geom":{
       "crs":{
         "type":"name",
         "properties":{
           "name":"EPSG:25832"
         }
       },
       "type":"Point",
       "coordinates":[
         359666.70366028673,
         5651728.682548149
       ]
     }
   }
 }
 }}}

-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/4799>
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