名称
CG_MinkowskiSum — 执行 Minkowski sum
大纲
geometry CG_MinkowskiSum(geometry geom1, geometry geom2);
描述
此函数执行点、线或多边形与多边形的 2D minkowski 和。
两个几何图形 A 和 B 的minkowski和是所有点的集合，这些点是 A 和 B 中任意点的和。minkowski和经常用于运动规划和计算机辅助设计。 有关更多详细信息在维基百科 Minkowski 添加。
第一个参数可以是任何 2D 几何图形（点、线串、多边形）。 如果传递 3D 几何图形，则会通过强制 Z 为 0 将其转换为 2D，从而可能导致无效的情况。 第二个参数必须是二维多边形。
实现利用 CGAL 2D Minkowskisum。
可用性：3.5.0
该方法需要SFCGAL后端。
示例
Minkowski sum of a LineString and a circular polygon. The line crosses the polygon, and the result sweeps the polygon along the line.
Code
WITH data AS (
SELECT ST_MakeLine(ST_Point(10, 10), ST_Point(100, 100)) AS line,
ST_Buffer('POINT(50 50)'::geometry, 30) AS circle
)
SELECT line AS input_line,
circle AS input_circle,
CG_MinkowskiSum(line, circle) AS minkowski_sum
FROM data;
栅格输出
LINESTRING(10 10,100 100) | POLYGON((80 50,79.424 44.147,77.716 38.519,74.944 33.333,71.213 28.787,66.667 25.056,61.481 22.284,55.853 20.576,50 20,44.147 20.576,38.519 22.284,33.333 25.056,28.787 28.787,25.056 33.333,22.284 38.519,20.576 44.147,20 50,20.576 55.853,22.284 61.481,25.056 66.667,28.787 71.213,33.333 74.944,38.519 77.716,44.147 79.424,50 80,55.853 79.424,61.481 77.716,66.667 74.944,71.213 71.213,74.944 66.667,77.716 61.481,79.424 55.853,80 50)) | MULTIPOLYGON(((179.424 155.853,177.716 161.481,174.944 166.667,171.213 171.213,166.667 174.944,161.481 177.716,155.853 179.424,150 180,144.147 179.424,138.519 177.716,133.333 174.944,128.787 171.213,38.787 81.213,35.056 76.667,32.284 71.481,30.576 65.853,30 60,30.576 54.147,32.284 48.519,35.056 43.333,38.787 38.787,43.333 35.056,48.519 32.284,54.147 30.576,60 30,65.853 30.576,71.481 32.284,76.667 35.056,81.213 38.787,171.213 128.787,174.944 133.333,177.716 138.519,179.424 144.147,180 150,179.424 155.853)))
Figure
Minkowski sum of a MultiPoint and a polygon. The result contains one translated copy of the polygon for each point.
Code
WITH data AS (
SELECT 'MULTIPOINT(25 50,70 25)'::geometry AS points,
'POLYGON((130 150,20 40,50 60,125 100,130 150))'::geometry AS polygon
)
SELECT points AS input_points,
polygon AS input_polygon,
CG_MinkowskiSum(points, polygon) AS minkowski_sum
FROM data;
栅格输出
MULTIPOINT((25 50),(70 25)) | POLYGON((130 150,20 40,50 60,125 100,130 150)) | MULTIPOLYGON(((45 90,75 110,150 150,155 200,45 90)),((90 65,120 85,195 125,200 175,90 65)))
Figure