====== SQLでGIS ======

===== バッファを求める =====
  * STBuffer

例）http://msdn.microsoft.com/ja-jp/magazine/dd434647.aspx
  DECLARE @Seattle geography = 'POLYGON(....)';
  SELECT c.customerid FROM customer c
    WHERE c.geog.STIntersects(@Seattle.STBuffer(10 * 1609.344));

==== 結合 ====
  * STUnion 

  * GeographyUnionAggregate

SQLSERVER2012から