adding MineT(X) functions for geography datatype

CHANGELOG.md

 Upcoming version:
 -----------------
+  - adding MineT(X) functions for geography datatype (Nikolaus Krismer)
   - moved berlin dataset to only be deployed on dbis-isochrone (Nikolaus Krismer)
   - added functions for MineT(X) algorithm to postgis/postgresql DB (Nikolaus Krismer)
   - updated gradle to version 3.0 (Nikolaus Krismer)

conf/pg_procedures_minet.sql

@@ -55,3 +55,20 @@ BEGIN
 END;
 $BODY$
   LANGUAGE plpgsql IMMUTABLE;
+
+CREATE OR REPLACE FUNCTION getTileEnvelope(geog geography, zoom integer)
+  RETURNS geography AS
+$BODY$
+DECLARE
+  _result geography;
+BEGIN
+    SELECT ST_MakeEnvelope(bbox.xmin, bbox.ymin, bbox.xmax, bbox.ymax, 4326)::geography INTO _result FROM (
+      SELECT tile2lon(tile.x, zoom) AS xmin, tile2lat(y, zoom) AS ymin, tile2lon(tile.x + 1, zoom) AS xmax, tile2lat(y + 1, zoom) AS ymax FROM (
+        SELECT lon2tile(ST_X(geog::geometry), zoom) AS x, lat2tile(ST_Y(geog::geometry), zoom) AS y
+      ) AS tile
+    ) AS bbox;
+
+    RETURN _result;
+END;
+$BODY$
+  LANGUAGE plpgsql IMMUTABLE;