Convert heatmap tiles to raster objects using ST_HMTAsRaster - ApsaraDB RDS

Converts a heatmap tile binary into a raster object for visualization and further computation.

Syntax

raster ST_HMTAsRaster(bytea hmt, text storageOption default '{}');

Parameters

Parameter	Description
`hmt`	The heatmap tile binary encoded in protobuf. To generate this value, use ST_AsHMT.
`storageOption`	The storage parameters for the raster object. If `chunk_table` is not specified, an anonymous temporary table is used. Default value: `{}`. For details, see ST_CreateRast.

Usage notes

The spatial reference (SRID) of the input heatmap tile must match the spatial reference of the output raster.
Pass the output of ST_AsHMT directly as the hmt argument.

Examples

The following example creates a test table with geometry points, generates a heatmap tile using ST_AsHMT, and converts it to a raster object using ST_HMTAsRaster.

CREATE TABLE test_table AS
SELECT i num,
    ST_SetSRID(ST_MakePoint((i-0.5)::numeric, (i-0.5)::numeric), 4326) geom,
    i*100::int4 weight,
    i*i*i::float8 volume
FROM generate_series(1, 10) i;

SELECT ST_HMTAsRaster(ST_AsHMT(geom,                          -- geometry type
    ST_MakeEnvelope(0, 0, 10, 10, 4326),                      -- extent
    10,                                                        -- width, in pixels
    10                                                         -- height, in pixels
))
FROM test_table;