ST_TileEnvelope — Creates a rectangular Polygon in Web Mercator (SRID:3857) using the XYZ tile system.
geometry ST_TileEnvelope(integer tileZoom, integer tileX, integer tileY, geometry bounds=SRID=3857;LINESTRING(-20037508.342789 -20037508.342789,20037508.342789 20037508.342789));
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
SELECT ST_AsText( ST_TileEnvelope(2, 1, 1) );
st_astext
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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
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POLYGON((-135 45,-135 67.5,-90 67.5,-90 45,-135 45))