Viewing posts by Gavin Fleming
School GIS task: create a 5km COVID-19 lockdown exercise buffer around your house
If you are doing some teaching in the classroom and some online and you are finding "blended teaching" overwhelming, this task is designed for asynchronous self study.
FOSS4G 2019 and QGIS in Bucharest
Open source GIS is alive and well and continues to grow in leaps and bounds around the world. Why so many Government entities in South Africa continue paying a fortune of tax-payers money for privative GIS and database software beats me, when wealthy, developed countries (as in most of Europe, for example) saw the light years ago and enthusiastically embrace FOSS.
Adding elevation to a line from a DEM in PostGIS and maintaining accurate measures
This is the second in a three part series on the behind-the-scenes GIS work that can go into planning a complex event, in this case the Cape Town Marathon.
How to create a point distance marker layer along a line in PostGIS
This is part 1 of a 3-part series.
Create a custom reference grid in QGIS composer
If you need to create a reference grid like this for your map, here's a simple method.
Introducing the first Tangible Landscape in Africa
As part of Kartoza's outreach programme, I recently helped the geography department at St Johns College in Johannesburg set up a Tangible Landscape, which to my knowledge is the first in Africa and possibly the first in a secondary school (most are at universities). I've been fascinated by these ever since I saw videos of them in action. So, when Samantha Jones and the rest of the St Johns geography department (Bridget Fleming-HOD, Brandon Louw and Keith Arlow), expressed a wish to have one in the department, Sam's husband, Matt, went ahead and built a frame. That was all the motivation I needed. Peter Henning, the IT Manager at St Johns, gathered an old i5 PC with 4GB RAM (running Ubuntu Linux) and some old monitors and a projector and ordered a Microsoft XBox Kinect. While Peter and Matt set up the infrastructure I set up up the software, mainly consisting of the Open Source GRASS GIS and the module that takes the point clouds coming in from the Kinect and converts them to raster digital elevation models (DEMs).
Mass reprojection of h5 files using gdal and bash tricks
I recently got hold of h5 files (Hierarchical Data Format (HDF)) and I tried to load them into QGIS and they were drawing in the wrong places.This was because they were not georeferenced. I set out to georeference them using GDAL. Since I was dealing with many h5 files I searched for an automated way to georeference them and could not find one complete solution hence I decided to do it myself with the help of Tim Sutton.
Opening for Junior Developer in Indonesia
We at Kartoza are Open Source geeks, specializing in software development and GIS. We’re expanding rapidly and looking to add a junior developer to our team that is passionate about problem solving and technologies. You will be part of an exciting web application development team.
Report back on the first QGIS User Conference in Nødebo, Denmark
I finally have some time to sit down and write up some thoughts on the QGIS User Conference and Developer Meeting (aka Hackfest) that we just held in Nødebo, Denmark. First up I need to thank Lene Fischer, who was the organiser and wowed us all with her relaxed and competent organisational approach to the conference. Thanks also to the University of Copenhagen School of Forestry - they sponsored the event by providing the venue and accommodation - and the venue was absolutely awesome with little cottages in the forest and all sorts of interesting diversions scattered around the forest. Lene gave me a list of names of people who helped to organise the event - I am sorry I have only got your first names but a very big thank you to you all!
How to run a Linux GUI application on OSX using Docker
Ok so here is the scenario:
7 tips for making productive use of docker
Generating an XYZ ASCII file from a QGIS raster
Someone wrote to me asking if it would be possible to generate an XYZ ASCII file from a single band raster layer in QGIS. No doubt there are more efficient ways (this approach is pretty slow but it works), but I thought it would be fun to show how you can iterate over a raster, writing out the value of each cell into a text file (along with the centroid coordinates for that cell).
How to create a QGIS PDF report with a few lines of python
Sometimes you want to automatically generate a report to reflect the latest state of your data. For example you may be capturing spatial data into a PostGIS database and want a snapshot of that every few hours expressed as a pdf report. This example shows you how you can quickly generate a pdf based on a QGIS project (.qgs file) and a QGIS template (.qpt file).
Alternatives to Google Maps Engine
Google will be supporting Google Maps Engine (GME) for only one more year. If your company uses GME or was thinking about it, you'll need to consider alternatives. Kartoza offers various alternatives depending on your use case. We are BoundlessGeo partners and offer support for the OpenGeo Suite in southern Africa. For more details of the Google announcement, including various scenarios where you should consider the OpenGeo Suite, see BoundlessGeo's take on it. Kartoza also offers development, support and training services across other components of the FOSS GIS stack that offer alternatives to Google and other proprietary products - we'd love to hear from you!
Opening for GIS generalist / spatial IT engineer at Kartoza
Kartoza is seeking GIS staff. We have a range of projects and challenges and will tailor the post to suit the ideal candidate.
Opening for Python developer at Kartoza
Kartoza is on the lookout for developers. We have a range of projects and challenges and will tailor the post to suit the ideal candidate.
QGIS course at AfQUA
Kartoza has just wrapped up a three-day Introduction to QGIS course that we gave pro bono at The African Quaternary: Environments, Ecology and Humans conference in Cape Town (AfQUA2015). Thank you to Kelly Kirsten from the local organising committee at the University of Cape Town for inviting us. Admire Nyakudya presented to about fifteen conference delegates from around the world. Attendees ran QGIS 2.6.1 on their own notebooks on the operating system of their choice. Some already use QGIS, some were experiencing QGIS for the first time and some some wanted to compare it with ArcGIS. The course content was guided largely by the QGIS training manual but as we usually do, adapted for the requirements, interests and pace of the class.
How to load a QGIS project in python
Today in a project we are working on we wanted to load a QGIS project. It takes surprisingly few lines of code to make a small standalone application that loads a project and then shows it as a map in a window like this:
A quick hack to select all multipart features in QGIS
Today we wanted to find all the multipart features in this layer:
Kartoza docker-helpers for lazy sysadmins
Docker is really awesome but typing out all those commands can get tedious. I wanted to quickly share a small project on github I made some time back that tries to make your life easier when working with docker. The project is called docker-helpers. It is a collection of bash scripts that give you short cuts to various 'every day' docker commands. Here is a quick listing of the different commands: