基于PostGIS的空间数据实时编辑与拓扑检查

1、基于PostGIS的空间数据实时编辑与拓扑检查CONTENTS 目录PART ONE 实时编辑PART TWO 空间拓扑010203PART THREE 拓展01数据编辑与问题优化C/S数据编辑用户GIS软件SHP、GDBGeoJSON用户浏览器服务端DBDBDBSHP、GDBGeoJSONB/S数据编辑数据操 作ST_SplitThe function supports splitting a line by (multi)point, (multi)line or (multi)polygon boundary, a (multi)polygon by line. The returned

2、 geometry is always a collection.Think of this function as the opposite of ST_Union.Theoretically applying ST_Union to the elements of the returned collection should always yield the original geometry.切割前切割后ST_UnionOutput type can be a MULTI*, single geometry, or Geometry Collection. Comes in 2 vari

3、ants. Variant 1 unions 2 geometries resulting in a new geometry with no intersecting regions.Variant 2 is an aggregate function that takes a set of geometries and unions them into a single ST_Geometry resulting in no intersecting regions.合并前合并后成功了 ？存在问题：切割后合并存在短线问题：ST_Buffer(geometry g1, float radiu

4、s_of_buffer, text buffer_style_parameters=)优化方案优化方案：ST_Snap(geometry input, geometry reference, float tolerance)ST_Buffergeometry ST_Buffer(geometry g1, float radius_of_buffer, text buffer_style_parameters=);geometry ST_Buffer(geometry g1, float radius_of_buffer, integer num_seg_quarter_circle);ST_B

5、uffergeometry ST_Buffer(geometry g1, float radius_of_buffer, text buffer_style_parameters=);geometry ST_Buffer(geometry g1, float radius_of_buffer, integer num_seg_quarter_circle);ST_Snapgeometry ST_Snap(geometry input, geometry reference, float tolerance);Snaps the vertices and segments of a geomet

6、ry to another Geometrys vertices. A snap distance tolerance is used to control where snapping is performed. The result geometry is the input geometry with the vertices snapped. If no snapping occurs then the input geometry is returned unchanged.Snapping one geometry to another can improve robustness

7、 for overlay operations by eliminating nearly-coincident edges (which cause problems during noding and intersection calculation).ST_SnapgeometryST_Snap(geometry input, geometry reference, float tolerance);ST_SnapgeometryST_Snap(geometry input, geometry reference, float tolerance);ST_SnapgeometryST_S

8、nap(geometry input, geometry reference, float tolerance);Note：ST_Buffer与ST_Snap的阈值大小正负值ST_Buffer处理后图形的有效性验证问题（ST_IsValid）02数据拓扑与问题优化哪些拓扑问题？超出边界面缝隙面重叠取相交部分：St_Intersection判断是否相交：St_IntersectsbooleanST_Intersects( geometry geomA , geometry geomB )SELECT ST_Intersects(POINT(0 0):geometry, LINESTRING (

9、2 0, 0 2 ):geometry); - fgeometryST_Intersection( geometry geomA , geometry geomB );SELECT ST_AsText(ST_Intersection(POINT(0 0):geometry, LINESTRING ( 0 0, 0 2 ):geometry); - POINT(0 0)取不相交部分： ST_SymDifferencegeometryST_SymDifference(geometry geomA, geometry geomB);SELECT ST_AsText( ST_SymDifference

10、( ST_GeomFromText(LINESTRING(50 100, 50 200),ST_GeomFromText(LINESTRING(50 50, 50 150) ) ); st_astext - MULTILINESTRING(50 150,50 200),(50 50,50 100)从A取与B不相交部分： ST_DifferencegeometryST_Difference(geometry geomA, geometry geomB);SELECT ST_AsText( ST_Difference( LINESTRING(50 100,50 200):geometry, LIN

11、ESTRING(50 50, 50 150):geometry ) ); st_astext - LINESTRING(50 150,50 200)如何实现？超出边界将内部面Union，命名为geom1外部大面命名为geom2ST_Difference（geom1，geom2）如何实现？面缝隙将内部面Union，命名为geom1外部大面命名为geom2ST_SymDifference（geom1，geom2如何实现？面重叠1.St_Intersection（geom1，geom2）成功了 ？存在问题：拓扑检查后出现很多小面：ST_Buffer(geometry g1, float radius

12、_of_buffer, text buffer_style_parameters=)优化方案优化方案：设置拓扑后出现结果的面积阈值Note：正负值ST_Buffer处理后图形的有效性验证问题（ST_IsValid， st_makeValid）相 交 后 结 果 是 否 为 面 ， 提 取 对 应 类 型 的 图 形 （ ST_CollectionExtract ）SRID丢失（ST_SetSrid）应用案例：第四次全国经济普查用户：5W*4村：66W小区：90W应用案例：第四次全国体育场地调查调查员用户：13W平台端用户：3000体育场地：300W场地管理单位：130W 调查员定位：950W应用案例：第七次全国人口普查03 拓展介绍ST_AsMvtST_AsMVTGeomgeometry ST_AsMVTGeom(geometry geom, box2d bounds, integer extent=4096, integer buffer=256, boolean clip_geom=true);bytea ST_AsMVT(anyelement row, text name, integer e