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Square Buffer
I was asked the other day how to create a square buffer around a linestring (or set of linestrings).
select sdo_geom.validate_geometry(c.geom,0.005) as validPoly, c.geom from (select sdo_geometry(2003,null,null,sdo_elem_info_array(1,1003,1),b.geom.sdo_ordinates) as geom from (select sdo_util.append(geom, sdo_geometry(2001,null,sdo_point_type(t.x,t.y,null),null,null)) as geom from (select sdo_util.append(sdo_geometry(2002,null,null,sdo_elem_info_array(1,2,1),sdo_ordinate_array(10,0,10,100)), sdo_util.reverse_linestring( sdo_geometry(2002,null,null,sdo_elem_info_array(1,2,1),sdo_ordinate_array(-10,0,-10,100)))) as geom from dual ) a, table(sdo_util.getVertices(a.geom)) t where t.id = 1 ) b ) c;
If you used my parallel function, then everything could be achieved as follows:
select sdo_geom.validate_geometry(c.geom,0.005) as validPoly, c.geom from (select sdo_geometry(2003,null,null,sdo_elem_info_array(1,1003,1),b.geom.sdo_ordinates) as geom from (select mdsys.sdo_util.append(geom, sdo_geometry(2001,null,sdo_point_type(t.x,t.y,null),null,null)) as geom from (select sdo_util.append(codesys.geom.parallel(a.geom,10,0.05), mdsys.sdo_util.reverse_linestring( codesys.geom.parallel(a.geom,-10,0.05))) as geom from my_linestrings l ) a, table(mdsys.sdo_util.getVertices(a.geom)) t where t.id = 1 ) b ) c;
Putting a PL/SQL function wrapper around this is trivial.
I hope this helps someone.
Documentation
- MySQL Spatial General Function Documentation
- Oracle LRS Object Documentation
- Oracle Spatial Exporter Package Documentation
- Oracle Spatial Object Function Documentation
- Oracle Spatial Object Function Documentation (Multi Page Version)
- PostGIS pl/pgSQL Function Documentation
- SC4O Oracle Java Topology Suite (Stored Procedures) Package Documentation
- SQL Server Spatial General TSQL Function Documentation
- SQL Server Spatial LRS TSQL Function Documentation