I had cause, today, to mark the location of something in Google Earth and then provide the longitude/latitude values to a website that wanted them in decimal degrees. Here is my location as a Google Placemark Location. Note that the longitude/latitude values are coded as formatted degrees, minutes and seconds as follows: Latitude Longitude 43�Read More
I have implemented an SDO_SetPoint/ST_SetPoint (PostGIS) function for Oracle. But in so doing I discovered the SE_VertexUpdate(geom ST_LineString,old ST_Point, new ST_Point) function that IBM has implemented. The interesting difference is that the ST_SetPoint function requires you to supply the original geometry, the new point value and the position of the point in the existing geometryRead More
As I indicated in my article on SDO_SetPoint PostGIS has a ST_SetPoint function that can be used to ‘Replace(s) point N of linestring with given point’. (And that IBM’s spatial database products have the SE_VertexUpdate() functions.) PostGIS also has the ST_RemovePoint function that “Removes point from a linestring”. The IBM Spatial Data Blade function isRead More
As I indicated in my article on SDO_SetPoint PostGIS has a ST_SetPoint function that can be used to “Replace(s) point N of linestring with given point”. (And that IBM’s spatial database products have the SE_VertexUpdate() functions.) PostGIS also has the ST_AddPoint function that “Adds a point to a LineString before point “. The IBM SpatialRead More
Anyone who has used an ESRI client software to edit data which is then stored in Oracle via ArcSDE has probably come across some peculiarly organised polygons that pass ArcSDE validation but not Oracle’s. (Note: Both products are OGC Simple Features Specification compliant. So why is this? In the main this is because ESRI’s ArcSDE pre-existedRead More
The GetVertices function in the MDSYS.SDO_UTIL package in Oracle Spatial is an exceedingly useful function. From the Oracle documentation of this function: This function returns an object of VERTEX_SET_TYPE, which consists of a table of objects of VERTEX_TYPE. Oracle Spatial defines the type VERTEX_SET_TYPE as: Oracle Spatial defines the object type VERTEX_TYPE as: The GetVerticesRead More
There was a posting over on the Oracle Spatial forum on Oracle Technet recently where a poster wanted to know how to fix the ordinates of an existing SDO_GEOMETRY object because the values that had been entered were incorrect (multiplied by 100000). This is the orginal post: bq. I was given a spatial network table,Read More
In PostGIS there is the ST_SetPoint() function that “Replace(s) point N of linestring with given point”. There is also the SE_VertexUpdate() extension function in IBM’s spatial products. (These are the sorts of oversights in the OGC and SQL/MM standards that I have commented on before.) There is no such function in Oracle so I thoughtRead More
I am continuing my looking at PostGIS and developing new functions for Oracle that plug-gaps identified in PostGIS. Much of this has been wrapping existing functions in my existing GEOM PL/SQL package, but some has involved developing new functions. Today, because of a comment on ST_Affine by Regina Obe, I added two additional wrappers forRead More