将pcpatch对象按指定方式压缩。
语法
pcpatch ST_compress(pcpatch pc, text global_compression_schema default '', text compression_config default '');
参数
| 参数名称 | 描述 |
|---|---|
| pc | pcpatch对象。 |
| global_compression_schema | 压缩框架。 |
| compression_config | 压缩配置项，指定具体维度的压缩算法。 |
描述
压缩框架可以为：
auto -- determined by pcid dimension laz -- no compression config supported ght -- is discarded
当压缩框架为dimension时，压缩配置项可以为：
auto -- determined automatically, from values stats zlib -- deflate compression sigbits -- significant bits removal rle -- run-length encoding
示例
SELECT ST_asText(ST_Compress(ST_MakePatch(1, ARRAY[-126.99,45.01,1,0, -126.98,45.02,2,0, -126.97,45.03,3,0])));
-------------------------------------------------
{"pcid":1,"pts":[
[-126.99,45.01,1,0],[-126.98,45.02,2,0],[-126.97,45.03,3,0]
]}
