CKAN is for data portals what QGIS is for GIS. The project describes itself as
CKAN is a powerful data management system that makes data accessible – by providing tools to streamline publishing, sharing, finding and using data. CKAN is aimed at data publishers wanting to make their data open and available.
Many open (government) data platforms rely on CKAN and while the web interface is pretty good, there’s still the hassle of finding and downloading the data using a web browser.
This is where the QGIS CKAN-Browser plugin comes in useful. The plugin has been developed by BergWerkGIS for the state of Carinthia, Austria and added to the public plugin repo earlier this year. CKAN-Browser comes preconfigured with some Austrian and European CKAN URLs for testing, so you can get going really quickly. It is easy to search for specific datasets or explore the portal’s data categories and it is just one click to download and load the data into your QGIS map:
Here’s a quick demo of loading a vector dataset as well as raster tiles:
For the full usage guide, visit the plugin’s Github page.
It’s great to see how well CKAN and QGIS can play together to enable seamless access to open data!
A while ago I wrote about the 5 meter elevation model of the city of Vienna. In the meantime the 5 meter model has been replaced by a 10 meter version.
For future reference, I’ve therefore published the 5 meter version on opendataportal.at.
details of the Viennese elevation model
I’ve been using the dataset to compare it to EU-DEM and NASA SRTM for energy estimation:
A. Graser, J. Asamer, M. Dragaschnig: “How to Reduce Range Anxiety? The Impact of Digital Elevation Model Quality on Energy Estimates for Electric Vehicles” (2014).
I hope someone else will find it useful as well because assembling the whole elevation model was quite a challenge.
mosaicking the rasterized WFS responses
DataCatalogs.org aims to be the most comprehensive list of open data catalogs in the world. […] The alpha version of DataCatalogs.org was launched at OKCon 2011 in Berlin.
As of today, 134 data catalogs have been registered. From Dalian, China to Rhode Island, data from all over the world is ready to be discovered.
Open data and open GIS – 2011 is an exciting year!
Vienna’s Open Government Data initiative is publishing an increasing amount of Geodata and the best thing is: They’re publishing it via open standardized services! Both WMS and WFS are available and ready to be used in QGIS.
Let’s see how we can use the data available through their WFS using the district information layer “Bezirksgrenzen” as an example. The page lists a GML and a GeoJSON version of WFS. For now, we’ll use GeoJSON.
In QGIS, the layer can be loaded using “Add vector layer” – “Protocol” and inserting the GeoJSON url there. The encoding should be changed to ISO8859-15 to account for “Umlaute”.
The loaded GeoJSON layer "Bezirksgrenzen"
Now, we have geodata. Let’s add some attribute data too! Attribute data is available in CSV format. After downloading e.g. some information on the district population, check the file content and remove excessive header lines so that there is only one header line containing attribute names left. Then, you can load the CSV file into QGIS too (“Add vector layer”).
Last step: Joining geodata and attribute data! Go to the vector layer’s properties – Join tab and add the following join relation:
Joining GeoJSON and attribute layer
Now, the attribute table of the vector layer contains the additional CSV attributes – ready for further analysis. If you want to classify based on numerical CSV attributes, you’ll have to create a .csvt file first otherwise all fields are interpreted as texts.
Works great. Thumbs up for this great initiative!
Please note that this post was written in 2011 and the server addresses have changed. Please refer to data.wien.gv.at for the latest links.
The city of Vienna has started their open data initiative. They’re offering data on a variety of topics, including: infrastructure, population, education, environment and traffic.
For use in GIS, they serve the data through WMS and WFS:
Both WMS and WFS work well with the developer version of QGIS.
Looking forward to new datasets. Announcements should be published via RSS feed.