一个点串超多的多边形

昨天从发现了一个我所见过的点串最多的多边形，简记一下：

该多边形一共包括接近30000个Part，包括5437611个点串：

SQL> select p.shape.numpts from testpolygon p where p.objectid=688;

SHAPE.NUMPTS

------------

     5437611

.csharpcode, .csharpcode pre{font-size: small;color: black;font-family: consolas, "Courier New", courier, monospace;background-color: #ffffff;/*white-space: pre;*/}.csharpcode pre { margin: 0em; }.csharpcode .rem { color: #008000; }.csharpcode .kwrd { color: #0000ff; }.csharpcode .str { color: #006080; }.csharpcode .op { color: #0000c0; }.csharpcode .preproc { color: #cc6633; }.csharpcode .asp { background-color: #ffff00; }.csharpcode .html { color: #800000; }.csharpcode .attr { color: #ff0000; }.csharpcode .alt {background-color: #f4f4f4;width: 100%;margin: 0em;}.csharpcode .lnum { color: #606060; }

这么多的点串，按照1个点两个double存储，使用16个字节，一共占用了

SQL> select 5437611*16/1024/1024||' M' from dual;

5437611*16/1024/1024|

---------------------

82.9713592529296875 M

.csharpcode, .csharpcode pre{font-size: small;color: black;font-family: consolas, "Courier New", courier, monospace;background-color: #ffffff;/*white-space: pre;*/}.csharpcode pre { margin: 0em; }.csharpcode .rem { color: #008000; }.csharpcode .kwrd { color: #0000ff; }.csharpcode .str { color: #006080; }.csharpcode .op { color: #0000c0; }.csharpcode .preproc { color: #cc6633; }.csharpcode .asp { background-color: #ffff00; }.csharpcode .html { color: #800000; }.csharpcode .attr { color: #ff0000; }.csharpcode .alt {background-color: #f4f4f4;width: 100%;margin: 0em;}.csharpcode .lnum { color: #606060; }

80多M，太庞大了。

但是到数据库中查询，

SQL> select dbms_lob.getlength(p.shape.points)/1024/1024 from testpolygon p where p.objectid=688;

DBMS_LOB.GETLENGTH(P.SHAPE.POINTS)/1024/1024

--------------------------------------------

                                  33.4238195

.csharpcode, .csharpcode pre{font-size: small;color: black;font-family: consolas, "Courier New", courier, monospace;background-color: #ffffff;/*white-space: pre;*/}.csharpcode pre { margin: 0em; }.csharpcode .rem { color: #008000; }.csharpcode .kwrd { color: #0000ff; }.csharpcode .str { color: #006080; }.csharpcode .op { color: #0000c0; }.csharpcode .preproc { color: #cc6633; }.csharpcode .asp { background-color: #ffff00; }.csharpcode .html { color: #800000; }.csharpcode .attr { color: #ff0000; }.csharpcode .alt {background-color: #f4f4f4;width: 100%;margin: 0em;}.csharpcode .lnum { color: #606060; }发现只用了33M的存储，这可能就是ArcSDE压缩的功能吧。