Open source GIS user group kicks off in Gauteng

January 6th, 2017, Published in Articles: PositionIT

 

The recently established South African QGIS User Group met for the first time in Gauteng on 25 November 2016, following the group’s Western Cape branch meeting two weeks prior. Convening at the Council for Scientific and Industrial Research’s (CSIR) offices in Pretoria, most of the members were drawn from academia and government departments.

QGIS is an open source GIS, and its local user group aims to offer help, support and share knowledge among members who use the software, as well as to coordinate development and gauge further software uses and needs in ways not currently catered for online.

Two technical presentations on the day focused on using QGIS in water resource applications, and were followed by a showcase of three plugins for the software.

First Bruno Meyer demonstrated how QGIS can be used as a remote sensing platform for water applications, using the South African National Space Agency’s (SANSA) Water Observation and Information System as example. Meyer, who recently retired from SANSA, demonstrated how the surface energy balance algorithm for land (SEBAL) model can be translated into a QGIS workflow (in the software’s graphical modeller), to extract evapotranspiration from Landsat 8 satellite imagery.

In a second presentation, geologist Immo Blecher explained how the software can be used in geohydrological modelling at the hand of his reconciliation project of water resources in the Limpopo North Water Management Area. For this project Blecher used data from connected spatial databases to create water resource management layers. His example showed how the Union/Dissolve tools can be used to create layer overlaps, and also highlighted the cartographic styling capabilities of the software.

After a brief discussion among members on the direction of the user group, Kartoza’s Gavin Fleming went on to highlight three QGIS plugins: Stream Feature Extractor, SG Diagram Downloader, and InaSAFE.

Plug-ins offer added or specialised functionality to the software, and of the three plug-ins, the SG Diagram Downloader, which allows SG diagrams to be downloaded from within the software, has enjoyed the most success locally. The Stream Feature Extractor can also come in handy for characterising street and river networks and in related analyses, Fleming explained. InaSAFE, the more novel of the three plugins, is a model simulation software for disaster management and planning, and relies on another open source project – OpenStreeMap.

Finally, considerations for choosing a spatial database were discussed, and those not already familiar with SpatiaLite (a spatial extension to SQLite) were introduced to the database software’s basics functions.

Attendees were also reminded of the upcoming FOSS4G Southern Africa and QGIS User Group Conference scheduled to take place in Johannesburg from 25 June 2017, and the next QGIS User Group meeting in Gauteng which is planned for 10 March 2017.