語法

float8[][] ST_HMTAsArray(bytea hmt);

返回值

返回一個二維的float8數(shù)組，每一個值代表熱力圖的統(tǒng)計值。

參數(shù)

描述

將熱力圖瓦片轉(zhuǎn)換為基于數(shù)組矩陣的表示方法，方便進行查看。 熱力圖瓦片需要通過ST_AsHMT函數(shù)生成。

示例

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_HMTAsArray(ST_AsHMT(geom, --geometry type
    ST_MakeEnvelope(0, 0, 10, 10, 4326), -- Extent
    10,        -- Width, in pixel
    10        -- height
))
FROM test_table;
---------
[0:9][0:9]={{1,0,0,0,0,0,0,0,0,0},{0,1,0,0,0,0,0,0,0,0},{0,0,1,0,0,0,0,0,0,0},{0,0,0,1,0,0,0,0,0,0},{0,0,0,0,1,0,0,0,0,0},{0,0,0,0,0,1,0,0,0,0},{0,0,0,0,0,0,1,0,0,0},{0,0,0,0,0,0,0,1,0,0},{0,0,0,0,0,0,0,0,1,0},{0,0,0,0,0,0,0,0,0,1}}