cartodb-postgresql/doc/CDB_HexagonGrid.md

Fill given extent with an hexagonal coverage

Using the function

Create a hexagonal grid from a polygon geometry. For example, take the geometry

  ST_SetSRID(
    ST_Envelope(
      ST_Collect(
        ST_MakePoint(10000000,-10000000),
        ST_MakePoint(-10000000,10000000)
      )
     ),
     3857)

We can create a grid as follows,

SELECT CDB_HexagonGrid(
  ST_SetSRID(
    ST_Envelope(
      ST_Collect(
        ST_MakePoint(10000000,-10000000),
        ST_MakePoint(-10000000,10000000)
      )
     ),
     3857),
   1000000) the_geom_webmercator

Which will look something like this,

Arguments

CDB_HexagonGrid(ext, side, origin)

• ext geometry. Extent to fill. Only hexagons with center point falling inside the extent (or at the lower or leftmost edge) will be emitted. The returned hexagons will have the same SRID as this extent.
• side float. Side measure for the hexagon. Maximum diameter will be 2 * side. Measure is in the same projection as ext
• origin OPTIONAL geometry. Optional origin to allow for exact tiling. If omitted the origin will be 0,0. The parameter is checked for having the same SRID as the extent.