Welcome to the Kartoza blog!
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.
This is part 1 of a 3-part series.
GIS practitioners and developers have long been interested in versioning spatial data. Luckily the folk at LocationTech have enabled us to do so through the provision of GeoGig (formerly geogit). Moreover, Geogig can interact with GeoServer seamlessly. At Kartoza we use Docker for orchestration of our services and as such it will form the backbone of this article.
Another doc about SSL? Maybe... We are writing this to explain our trial and error on setup SSL on the servers. You might have read somewhere about setting up SSL (so have we, and it's painful).
Our blog is based on hands-on experience and hopefully you can learn something from it.
I preface this article by saying that what I am showing here is probably not best practice and you should test to see if it works reliably for you before taking this route. I should also mention that this is a hacky approach because it breaks our ‘never log on to a server’ rule, so it is not a long-term solution - it is a short-term hack until Hetzner adds a cloud storage offering to their cloud platform.
Well, QGIS 3 has been out for a couple of weeks now with lots of new functionality. While you are still feeling your way around all the new features I thought I could highlight some of the improvements to the browser panel that will make you fall further in love with QGIS.
As a leading Open Source GIS company, Kartoza aims to introduce people and organisations to the world of Open Source GIS in South Africa. The majority of educational institutions in South Africa still teach students GIS and Remote Sensing using proprietary software. During the last few years, there has been a steady increase in institutions migrating to using Open Source GIS systems.
Kartoza is always on the lookout for young and talented students to enroll them in our vacation work or internship program with a possibility of employment. The following story is the experience from our most recent intern, Natalia Dambe, a Master's Student at the University of Cape Town. In her words:
Kartoza recently published the CoGo Plugin (aka Parcel Plugin) in the QGIS plugin repository. This plugin expands the group of plugins designed to manage SDI (Spatial Data Infrastructure). CoGo ('coordinate geometry') refers to its ability to handle both types of coordinates used in land surveying, namely cartesian coordinates (x,y; long/lat) and polar coordinates (bearing and distance).
I have been playing around with roads layers and wanted to change the line directions for some of my features. I looked around for solutions to do this in QGIS and saw that I could use the swap vector direction plugin in QGIS or ST_reverse in PostgreSQL. But I wanted to find a non destructive way to do this as I did not want to alter my data. I decided to try the geometry generator in QGIS.
If you are using QGIS 3 master builds on MacOS and encounter issues with the display of processing dialog layouts like this:
If you need to create a reference grid like this for your map, here's a simple method.
Four of the Kartoza team (Tim, Etienne, Ismail and Rizky) attended the GeoNode Summit in Rome held in November 2016. The World Food Programme provided the venue for the event and our attendance was funded by the WorldBank/GFDRR. The event was a really great opportunity to interact with the GeoNode community. We used the opportunity to learn about the upcoming plans for GeoNode and discuss some of our own plans.
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).
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.
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.
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!
Ok so here is the scenario:
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).