There was a recent discussion about renewing PostGIS’s OGC Certificates. The discussion was interesting as it goes to the heart of the value of certification in the light of the evolution of standards. The contribution to the discussion was mostly an observation about product value and market positioning. And the standards I had in mindRead More
Over the years I have made available functions that generate the tiles of a grid given user input. These have been made available in Oracle, PostGIS and SQL Server Spatial (geometry). Here are the type signatures of these functions: Oracle Object Oracle Package PostGIS SQL Server Geometry Requirement A customer has the requirement to generationRead More
Note This is an article I wrote some years back which I have ported to my new website. Introduction There are a large number of geospatial data storage, delivery and interchange formats around nowadays. Including (I limit this discussion to vector data formats only): Geography Markup Language (GML) Keyhole Markup Language GPS eXchange Format (GPX)Read More
Introduction This article is about importing Victorian Government’s Incremental Update File (IUF) XML data into SQL Server. The IUF XML is used to publish whole (complete) datasets (e.g. Local Government Areas) or deltas/changes. As will be seen, it encodes geometry objects in its own unique way, and thus is a good dataset to demonstrate theRead More
A colleague asked me the other day how he could move data from a table in an Oracle database with a geometry column to SQL server. Of course I thought of this as a straight forward data migration exercise using standard database tools, in this case SQL Developer and SQL Server Management Studio (SSMS), whereRead More
STMulti — Function that returns @p_geometry as a MULTI* geometry Function Specification Description In situations where a geometry column is constrained to hold only the multi version of a base geometry, storage of a single geometry eg LineString requires that geometry to be wrapped as a multi geometry eg MultiLineString. ALTER TABLE [dbo].[Colony] WITH CHECKRead More
STRound — Function which rounds the ordinates of the supplied geometry. Function Specification Description The result of many geoprocessing operations in any spatial type can be geometries whose ordinates (X, Y etc) have far more decimal digits of precision than the initial geometry. Additionally, some input GIS formats, such as shapefiles (which has no associatedRead More
Using PostgreSQL’s XML processing to load spatial data Spatial data comes in many forms, but the most common is, probably, XML. If you have a need to load XML data – whether that be GML or other XML with spatial data – you may not know it, but you can use native PostgreSQL tools toRead More
STPointToCircularArc — Return a measured point by snapping provided point to the provided CircularString Function Specification Description This function snaps supplied point to @p_circularString, returning the snapped point. Computes Z and M values if exist on @p_circularString. If input @p_circularString is 2D, length from start of @p_circularString to point is returned in M ordinate ofRead More
STLocateBetweenElevations — Computes and returns elements that intersect the specified Z range. Function Specification Description Is implementation of PostGIS: Processes the supplied (3D, 3DM) (multi)linestring returning the elements that intersect the specified range of elevations inclusively. May return points and/or linestrings in the appropriate geometry type. Where a new xy position is to be computed,Read More