PostGIS中几何对象输出

select myID AS ID,ST_AsText(pt) AS geo from test1;
//以文本格式返回

select *,ST_AsGeoJson(pt) from test1
//以json格式返回

select *,ST_AsGML(pt) from test1

//以gml格式返回

几何对象输出：
NDR：Little Endian
XDR：big-endian
HEXEWKB：Canonical
SVG：SVG 格式
GML：GML 格式
KML：KML 格式
GeoJson：GeoJson 格式

ST_AsBinary(geometry,{'NDR'|'XDR'})
ST_AsEWKT(geometry)
ST_AsEWKB(geometry, {'NDR'|'XDR'})
ST_AsHEXEWKB(geometry, {'NDR'|'XDR'})
ST_AsSVG(geometry, [rel], [precision])
ST_AsGML([version], geometry, [precision])
ST_AsKML([version], geometry, [precision])
ST_AsGeoJson([version], geometry, [precision], [options])