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 both make available whole datasets (eg Local Government Areas) or deltas/changes. As will be seen it encodes the geometry objects in its own unique way thus is a good dataset to demonstrateRead 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
STLineSubstring — Returns a substring of the providec linestring starting and ending at the given fractions (between 0 and 1) of total 2D length or measure range. Function Specification Description Given a start and end measure, this function extracts the line segment defined between them (a point if start=end). If a non-zero value is suppliedRead More
STLineInterpolatePoint is a PostGIS like function that returns point geometry at supplied fraction along linestring.