H2GIS

Fork me on GitHub

GeoJsonWrite

Signature

GeoJsonWrite(VARCHAR path, VARCHAR tableName);
GeoJsonWrite(VARCHAR path, VARCHAR tableName, VARCHAR fileEncoding);

Description

Writes the contents of table tableName to a GeoJSON file located at path.

tableName can be either:

  • the name of an existing table,
  • the result of a query (SELECT instruction which has to be written between simple quote and parenthesis '( )').

The default value of fileEncoding is ISO-8859-1.

Examples

-- Write a spatial table to a GeoJSON file:
CREATE TABLE TEST(ID INT PRIMARY KEY, THE_GEOM POINT);
INSERT INTO TEST VALUES (1, 'POINT(0 1)');
INSERT INTO TEST VALUES (2, 'POINT(2 4)');

CALL GeoJsonWrite('/home/user/test.geojson', 'TEST');

-- Read it back:
CALL GeoJsonRead('/home/user/test.geojson', 'TEST2');
SELECT * FROM TEST2;
-- Answer:
-- | THE_GEOM    | ID |
-- |-------------|----|
-- | POINT(0 1)  | 1  |
-- | POINT(2 4)  | 2  |

Case where tablename is the result of a selection

CALL GeoJsonWrite('/home/user/test.geojson', 
                  '(SELECT * FROM TEST WHERE ID<2 )');

-- Read it back:
CALL GeoJsonRead('/home/user/test.geojson', 'TEST2');
SELECT * FROM TEST2;
-- Answer:
-- | THE_GEOM    | ID |
-- |-------------|----|
-- | POINT(0 1)  | 1  |
See also