## Name

ST_CoverageSimplify — 简化多边形覆盖范围边缘的窗口函数。

## Synopsis

`geometry ST_CoverageSimplify(`geometry winset geom, float8 tolerance, boolean simplifyBoundary = true`)`;

## 描述

 如果输入不是有效的覆盖范围，则输出中可能会出现意外的伪影（例如边界交叉点或看似共享的分离边界）。 使用 ST_CoverageInvalidEdges 确定覆盖范围是否有效。

## 示例

 输入覆盖范围 简化覆盖范围
```WITH coverage(id, geom) AS (VALUES
(1, 'POLYGON ((160 150, 110 130, 90 100, 90 70, 60 60, 50 10, 30 30, 40 50, 25 40, 10 60, 30 100, 30 120, 20 170, 60 180, 90 190, 130 180, 130 160, 160 150), (40 160, 50 140, 66 125, 60 100, 80 140, 90 170, 60 160, 40 160))'::geometry),
(2, 'POLYGON ((40 160, 60 160, 90 170, 80 140, 60 100, 66 125, 50 140, 40 160))'::geometry),
(3, 'POLYGON ((110 130, 160 50, 140 50, 120 33, 90 30, 50 10, 60 60, 90 70, 90 100, 110 130))'::geometry),
(4, 'POLYGON ((160 150, 150 120, 160 90, 160 50, 110 130, 160 150))'::geometry)
)
SELECT id, ST_AsText(ST_CoverageSimplify(geom, 30) OVER ())
FROM coverage;

id |               st_astext
----+---------------------------------------
1 | POLYGON ((160 150, 110 130, 50 10, 10 60, 20 170, 90 190, 160 150), (40 160, 66 125, 90 170, 40 160))
2 | POLYGON ((40 160, 66 125, 90 170, 40 160))
3 | POLYGON ((110 130, 160 50, 50 10, 110 130))
4 | POLYGON ((160 150, 160 50, 110 130, 160 150))
```