Great news for all Oracle Spatial users: Locator is no more! So no longer do I have a write blog article constantly referring to Oracle Spatial or Locator: now it is just Oracle Spatial. And Spatial is no longer a separately licensed product for Enterprise Edition: it is simply available to anyone with a validRead More
Introduction A lot has been written, positive and negative, about the speed of Oracle Spatial over the years, a lot of ill informed (I mean if you don’t use it, how can you criticize it?). But since Oracle Database 12c (12.1) there is no longer any doubt as to the speed of the product. Why?Read More
Introduction I have written a complete package of Linear Referencing functions in TSQL. They have been available for over two years. They have not been well advertised so here is an attempt to do so. The following tests expose pretty well all the functions in the package (they include some utility functions like STSegmentize). TheRead More
Introduction The OGC operators for geometry processing only support two polygon inputs. Additionally the Microsoft aggregate operators only include geometry union processing geometry::UnionAggregate and not overlay processing etc. UnionAggregate returns for all input polygons as the single Union (see above) does. Concept: Resolving all overlapping areas, without dissolving boundaries, is called “planar enforcing”. Planar enforcementRead More
Introduction Warning: This article is long mainly because it includes the source code of the Hilbert, Morton and Peano key/curves. I would assert that space filling curves have always been overlooked in their use within GIS. Their existence was/is rarely taught at Universities, though at least in my day. Perhaps today it is different (butRead More
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
GIS Desktop Software is the bedrock of how most people experience Geographic Information Systems. A limited selection of such products are: ArcGIS Manifold MapInfo qGIS FME (Feature Manipulation Engine) – not strictly a GIS but it can do most of the above. I have experience with all of the above. If anyone wants some help,Read More
This article shows how to geocode points objects against grid cells without using spatial operators. The article also shows how to use space curve values such as generated by a Morton key algorithm as grid cell ids and thus geocodes.
The lack of an array datatype in TSQL can be overcome for geometry processing by use of a GeometryCollection as a data type and a set of methods to manipulate it.
In some situations Quadrilateral polygon geometries in SQL Server Spatial can affect processing results. The best example of this is the identification of CircularStrings in polygon geometries. If quadrilateral objects are not identified, they end up being incorrectly converted. This function helps identify such polygon objects.