Question

我有一个带有SRID 3857数据的几何字段的PostGIS表。我想将几何质心作为纬度/经度坐标，但似乎无法正确转换值：

SELECT 
ST_X(ST_CENTROID(geometry)),
ST_Y(ST_CENTROID(geometry)),
ST_X(ST_TRANSFORM(ST_CENTROID(geometry),3857)) AS LONG, 
ST_Y(ST_CENTROID(ST_TRANSFORM(geometry,3857))) AS LAT
FROM my_table

=> -8220067.19453888107、4997528.08142071683，-8220067.19453888107、4997528.08142071683

Answer 1

您正在使用{/ 3}}（伪墨卡托），它不是经度/纬度，而是米。

要获取经度/纬度值，您需要使用3857 projection：

db=# SELECT
ST_X(ST_Centroid(geometry)),
ST_Y(ST_Centroid(geometry)),
ST_X(ST_Centroid(ST_Transform(geometry, 4326))) AS long,
ST_Y(ST_Centroid(ST_Transform(geometry, 4326))) AS lat
FROM my_table;
       st_x        |       st_y       |       long        |       lat
-------------------+------------------+-------------------+------------------
 -8220067.19453888 | 4997528.08142072 | -73.8421199734375 | 40.8994922746749
(1 row)

从PostGIS点获取纬度/经度

1 个答案: