This topic describes the ST_HMTAsRaster function. This function converts heatmap tiles into raster objects for easier viewing and computing.
Syntax
raster ST_HMTAsArray(bytea hmt, text storageOption default '{}');Parameters
Parameter | Description |
hmt | The heatmap tile binary based on protobuf. |
storageOption | The storage parameters of the raster object. If the chunk_table parameter is not specified, an anonymous temporary table is used. For more information, see ST_CreateRast. |
Description
This function converts heatmap tiles into raster objects for easier viewing and computing. Heatmap tiles are generated by using the ST_AsHMT function.
The spatial reference here must be the same as the spatial reference in the heatmap.
Examples
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 pixel
10 -- height
))
FROM test_table;
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