This blog presents functions for Bing Maps Tile System for TSQL. This support includes converting Latitude/Longitude pairs to Bing Maps QuadKeys. The source for the functions is over at the Mircosoft site – an article by James Schwartz. They are donated to the public domain. Some tests include: I hope this is of use toRead More
Today (25th February 2015) I uploaded the following changes to the following packages: 1. TESSELATE Reduce complexity of package interface. Removed all Quad_Tree Initialise procedures (Quad_Tree functions internally initialise). All SPACE_KEY functions removed: package now only supports morton key generation. Added new ST_TileGeometry functions that provide greater options for tiling (or generating a regular gridRead More
I wrote an article on Gridding a PostGIS Geometry object a while back. I had cause, recently, to use a variation on this for the generation of an array of point objects for a geometry polygon, so I wrote a version that also allows for the generation of a grid of polygons or points dependingRead More
It is often observed that you cannot use an sdo_geometry object in an ORDER BY clause of a SELECT statement. This is demonstrated below. Test Data Now, if we try and sort this data we get: If you look at the SDO_GEOMETRY type you will see that it does not have a MAP or ORDERRead More
A common question that comes up in the various database forums (PostGIS, SQL Server, Oracle) is how to “grid” a linear or polygonal object. By “grid” one means work out the square pixels (rectangular polygons) that cover or define a vector geometry. Here is some SQL for doing this for Oracle Locator. Single Geometry HereRead More
A common question that comes up in the various database forums (PostGIS, SQL Server, Oracle) is how to “grid” a linear or polygonal object. By “grid” one means work out the square pixels (rectangular polygons) that cover or define a vector geometry. Here is some SQL for doing this for PostGIS. Single Geometry The followingRead More
A common question that comes up in the various database forums (PostGIS, SQL Server, Oracle) is how to “grid” a linear or polygonal object. By “grid” one means work out the square pixels (rectangular polygons) that cover or define a vector geometry. Here is some SQL for doing this for SQL Server 2008 Denali. DenaliRead More
In my article on the creation and use of a space keys for the spatial sorting of spatial data, I show how to implement a Morton key for PostgreSQL/PostGIS pl/pgSQL. The function is as follows: Now, let’s test it with some simple SQL: Results I hope this is of use to someone.
One of the things that should be taught to GIS students at Uni but isn’t in a lot of courses is the notion of space keys or space-filling curves. The mathematics behind these keys was done before computing by mathematicians like: Giuseppe Peano David Hilbert The one that most GIS people are introduced to isRead More