ST_TileEnvelope
Name
ST_TileEnvelope — Creates a rectangular Polygon in Web Mercator (SRID:3857) using the XYZ tile system .
Synopsis
geometry
ST_TileEnvelope
(
integer
tileZoom
, integer
tileX
, integer
tileY
, geometry
bounds=SRID=3857;LINESTRING(-20037508.342789 -20037508.342789,20037508.342789 20037508.342789)
)
;
Description
Creates a rectangular Polygon in Web Mercator (SRID:3857) using the XYZ tile system . By default, the bounds are the in EPSG:3857 using the standard range of the Web Mercator system (-20037508.342789, 20037508.342789). The optional bounds parameter can be used to generate envelopes for any tiling scheme: provide a geometry that has the SRID and extent of the initial "zoom level zero" square within which the tile system is to be inscribed.
Availability: 3.0
Example: Building a tile envelope
SELECT ST_AsText( ST_TileEnvelope(2, 1, 1) );
st_astext
------------------------------
POLYGON((-10018754.1713945 0,-10018754.1713945 10018754.1713945,0 10018754.1713945,0 0,-10018754.1713945 0))
SELECT ST_AsText( ST_TileEnvelope(3, 1, 1, ST_MakeEnvelope(-180, -90, 180, 90, 4326) ) );
st_astext
------------------------------------------------------
POLYGON((-135 45,-135 67.5,-90 67.5,-90 45,-135 45))