So you have moved your spatial data into PostGIS and everything is great….until you start wanting to clip it out again. Luckily clipping data within the postgres environment is trivial with the little help of SQL. However I wanted something a little more fancy – a way to iterate through all my spatial tables and… Read more »
Introduction PyWPS is a great project by Jachym Cepicky and Intevation to provide an open (Open Source and Open Standards) implementation of the OGC Web Processing Service spec. In this article, I will give a quick run through of getting up and running enough to have the obligatory “Hello World” service running. Check out and… Read more »
If you are a keen GDAL user, you have probably noticed by now that you can extract a rectangular portion of an image into a new image. Sometimes you want to go a little further and actually extract only the cells within a polygonal area from a shapefile or similar vector file. In this article… Read more »
We just released QGIS 1.3 ‘Mimas’. Download your copy http://qgis.org/en/download/current-software.html and read the official announcement over on the QGIS blog here I did some revisions to the Windows all in one installer for this release and was able to shrink it down in size quite a bit – always good news for those of us… Read more »
Every day being a QGIS user and developer brings a new surprise. Even more so since the python language bindings were introduced to allow people to write plugins easily. Today Andreas Plesch popped a note to the dev list saying he had created a plugin for hill shading. I often like to use a hill… Read more »
Intro A client recently asked me to prepare some aeronautical data for use with QGIS. The data was supplied in about twenty 8 bit paletted GeoTiff images. The client wanted to produce a seamless mosaic so that operators only needed to open a single file to view the rasters. Also he wanted good read access… Read more »
At one of my clients we manage a petabyte heirachical storage system (mixed offline tape storage, near-line cache storage and online disk storage) and several high capacity (e.g. 15TB) SAN enclosures. These devices are not cheap. However, all is not lost – there is a blog post from BackBlaze thats doing the rounds on the… Read more »
Eric Raymond and others worked hard to produce and excellent guide on how to ask smart questions. I often give talks about QGIS or open source development in general and I usually end it with a slide or two about how to get help, in which I cover some of the same topics listed in… Read more »
A common activity when building a web application is the ‘tweak code -> reload page -> view page source’ cycle. Obviously this gets a bit time consuming and boring after a while. Under Firefox you can use tools like firebug to dynamically inspect and alter the source for your web page, but it adds quite… Read more »
I was recently interviewed for an article on open access to geospatial data in the City of Johannesburg. The article has been published online now for all to enjoy…