Simon Greener

Generating Road LineStrings with Z (Elevation) through processing involving a Tasmanian statewide Digital Elevation Model (DEM)

04 Sep 2026 By Simon Greener

This article shows how to create a 3D road centreline dataset from 2D LineStrings for the whole of Tasmania. The elevation data is sourced from a rectangular grid of XYZ points which are converted into three vertex PolygonZ triangles (a form of a TIN). The 2D road centreline LineStrings are converted to 3D by processing each vertex against the triangle it falls in, interpolating the Z value from that triangle, and recompiling a final LineStringZ object from the individual PointZ vertices. The final result is visualized by use of pgAdmin’s Graph Visualizer.

Best Practice when Loading geographic Polygons into SQL Server Spatial geometry column

02 Sep 2026 By Simon Greener

This article describes a best practice to loading geographic polygons into SQL Server Spatial geometry column through guaranteeing correct coordinate winding order. It mentions FME’s Orientor transformer as a specific tool for when loading data.

Converting PostgreSQL Native Geometric Types to PostGIS

17 May 2024 By Simon Greener

Introduction I comes as a surprise to some that PostgreSQL has it own native geometric type system. The geometric types are documented here but the list includes: point – Point on a plane – (x,y) lseg – Finite line segment – ((x1,y1),(x2,y2)) box – Rectangular box – ((x1,y1),(x2,y2)) path – Closed path (similar to polygon)Read More

Killer Data

14 May 2022 By Simon Greener

Back in 2005 I wrote two article on LiDAR. These articles are: Killer Apps – Part 1 (Here is a text version of the article.) I have been musing about some threads relating to data for a while and I’ve noticed they have been tangling people up.These threads resonated at the recent Spatial Sciences InstituteRead More