Create GeoJSON Document from Selection of SDO_Geometry objects.
The SDO2GEOJSON function available on this website converts a single SDO_GEOMETRY object to a GeoJSON Snippet.
Here we present a procedure that creates an GeoJSON document from a collection of SDO_GEOMETRY objects in a SQL SELECT ref_cursor:
CREATE OR REPLACE FUNCTION sdo2geojson_document(r_cur SYS_REFCURSOR) RETURN CLOB deterministic IS GEOM MDSYS.SDO_GEOMETRY; js_geom CLOB; j_geom CLOB; start_tag VARCHAR2(100); end_tag VARCHAR2(100); BEGIN DBMS_LOB.CREATETEMPORARY (LOB_LOC => JS_GEOM, cache => TRUE); start_tag := '{ "type": "FeatureCollection", "features": ['; DBMS_LOB.WRITE(LOB_LOC => JS_GEOM, AMOUNT => LENGTH(START_TAG), OFFSET => DBMS_LOB.GETLENGTH(JS_GEOM)+1, buffer => start_tag ); LOOP FETCH r_cur INTO geom; EXIT WHEN R_CUR%NOTFOUND; J_GEOM := SDO2GEOJSON(GEOM); DBMS_LOB.APPEND(dest_lob => JS_GEOM, src_lob => j_geom ); END LOOP; end_tag := '] }'; DBMS_LOB.WRITE(LOB_LOC => JS_GEOM, AMOUNT => LENGTH(END_TAG), OFFSET => DBMS_LOB.GETLENGTH(JS_GEOM)+1, buffer => end_tag ); RETURN JS_GEOM; END;
I hope this is of use to someone.