计算点距离50英里(北,东北45%,西南45%) [英] Caculate point 50 miles away (North, 45% NE, 45% SW)
问题描述
在PostGIS中,有没有一种方法可以计算出50英里外的不同方向上的另一个点?
In PostGIS, Is there a way to calculate another point 50 miles away in different directions?
给出一个点(纽约",-74.00,40.71),我该如何计算以下点?
Given a point, ('New York',-74.00,40.71), how do I calculate the following points?
1) 50 miles directly North
2) 50 miles 45% North East
4) 50 miles directly East
3) 50 miles 45% South West
更新: 似乎 http://postgis.net/docs/ST_Project.html 可能是解决方案.
Update: It seems http://postgis.net/docs/ST_Project.html may be the solution.
ST_Project('POINT(-74.00 40.71)'::geography, 80467.2, radians(45.0))
但是,我需要参考数据库记录来做到这一点.而不是硬编码.
However, I need to reference the database record to do it. not hard code it.
推荐答案
尝试结合 ST_Project
带有 CTE
的a>-调整
Try combining ST_Project
with a CTE
- adjust the values of radians
to the azimuth you need.
WITH j AS (
SELECT poi::geography AS poi FROM t
)
SELECT
ST_AsText(ST_Project(j.poi, 80467.2, radians(90.0)),2),
ST_AsText(ST_Project(j.poi, 80467.2, radians(45.0)),2),
ST_AsText(ST_Project(j.poi, 80467.2, radians(180.0)),2),
ST_AsText(ST_Project(j.poi, 80467.2, radians(135.0)),2),
ST_AsText(ST_Project(j.poi, 80467.2, radians(270.0)),2),
ST_AsText(ST_Project(j.poi, 80467.2, radians(225.0)),2),
ST_AsText(ST_Project(j.poi, 80467.2, radians(360.0)),2),
ST_AsText(ST_Project(j.poi, 80467.2, radians(315.0)),2)
FROM j;
st_astext | st_astext | st_astext | st_astext | st_astext | st_astext | st_astext | st_astext
---------------------+---------------------+------------------+--------------------+---------------------+--------------------+------------------+---------------------
POINT(-73.05 40.71) | POINT(-73.32 41.22) | POINT(-74 39.99) | POINT(-73.33 40.2) | POINT(-74.95 40.71) | POINT(-74.67 40.2) | POINT(-74 41.43) | POINT(-74.68 41.22)
(1 Zeile)
注意:图像中的缓冲区仅用于说明.
Note: The buffer in the image is just for illustration.
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