將二維幾何對象轉換為H3網格表達。
文法
h3grid[] ST_AsH3Grid(geometry geom, integer precision, bool degenerated default false);參數
參數名稱 | 描述 |
geom | 需要計算網格對象的幾何對象。 |
precision | 精度層級，取值範圍：0~15。 |
degenerated | 是否採用退化網格。 |
描述
退化網格原理與H3相同。
SRID可以為任何投影，函數會自動完成投影轉換。
樣本
-- POINT
select ST_AsH3Grid(st_geomfromtext('POINT(2932234 234234)',28992),4);
st_ash3grid
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{010101FFFFFFFF09D54208}
--LINESTRING
select st_ash3grid('SRID=4326;LINESTRING(122.48077 51.72814,122.47416 51.73714)'::geometry, 10);
st_ash3grid
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{010100FFFF59698658A108,010100FF7F58698658A108,010100FFFF5A698658A108,010100FF7F51698658A108,010100FF7F50698658A108,010100FF7F52698658A108,010100FF7FCD698658A108,010100FF7FCF698658A108,010100FF7FCE698658A108,010100FFFFC0698658A108,010100FF7FC7698658A108,010100FFFFD5698658A108}
(1 row)
-- MULTIPOLYGON
SELECT ST_AsH3Grid('SRID=4326;MULTIPOLYGON(((0 0,10 0,10 10,0 10,0 0),(2 2,2 5,5 5,5 2,2 2))) '::geometry, 2);
st_ash3grid
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{010100FFFFFFFF7F882508,010100FFFFFFFF7F2C2808,010100FFFFFFFF7F2D2808,010100FFFFFFFF7F8B2508,010100FFFFFFFF7F2F2808,010100FFFFFFFF7F8D2508,010100FFFFFFFF7F892508,010100FFFFFFFF7F8F2508,010100FFFFFFFF7F542708,010100FFFFFFFF7F572708,010100FFFFFFFFFF882508,010100FFFFFFFFFF892508,010100FFFFFFFFFF2D2808,010100FFFFFFFFFF2E2808,010100FFFFFFFFFF8A2508,010100FFFFFFFFFF5708}
(1 row)