This week I had the privilege of coordinating a workshop on QGIS and remote sensing in Kampala, Uganda. Our trainers were Thomas Ballatore and Shane Bradt. We were very pleased with their walkthroughs and presentations of crucial software and plugins. The training is part of the Norwegian Oil for Development Program.
The focus was of course QGIS. But to be hones BEAM Visat was a real eye-opener. Yes, I have been introduced to the software while working in an expert group on satellite imagery. We earlier this year concluded a report for the Norwegian Space Centre where BEAM Visat was mentioned as one of several crucial components for handling remote sensing data. But – the workshop provided an applied context which gave me a whole new perspective to both software and methods.
Apart from me and my fellow coordinator, Ingunn Limstrand, participants were high level practitioners from the Ugandan GIS community. They were from the National Environment Managemt Authority, National Forest authority, Uganda Wildlife Authority, The Directorate of Water Resources Management, The Petroleum Exploration and Production Department (PEPD) and many more.
The training was held at the Speke Resort Hotel in Kampala, Uganda. This is a picture of the participants:
The training was base daround the following software:
QGIS has grown and with its plugins represents a fully fledged geographical information system. QGIS allows the user to handle many of the industrial standard file and database formats. To find this as an open source product not only proves that working without ESRI software is possible. It also proves that ESRI should continue to refine their own software and pricing policy. Nurturing an ever growing list of plugins QGIS continues to reach out to an increasing number of users.
The BEAM (Basic ENVISAT Toolbox for (A) ATSR and MERIS) Earth Observation Toolbox and Development Platform is open source software developed by Brockmann Consult GmbH on behalf of ESA. It consists of a collection of executable tools and Application Programming Interfaces (APIs) for utilization, viewing, processing and analyzing satellite data. BEAM was primarily developed as an ENVISAT/MERIS toolbox, but has since evolved to a toolbox processing Earth observation data in general. BEAM supports raster data formats, such as GeoTIFF and NetCDF and data format from other Earth Observation (EO) sensors than Envisat’s optical instrument MERIS (MEdium Resolution Imaging Spectrometer) such as MODIS L2 on Aqua and Terra and TM on Landsat 5. It also supports Landsat 8 data sets.
QGIS plugin: Semi Automatic Classification Plugin
Indeed a useful tool making it possible for QGIS to do semi-automatic supervised classification of remote sensing images, providing tools to expedite the creation of ROIs, the pre processing phases (image clipping, Landsat conversion to reflectance), the land cover classification process, and the post processing phases (accuracy assessment, land cover change).
QGIS plugin: Orefo Toolbox plugin
The Orefo Toolbox is distributed as an open source library of image processing algorithms. We learnt a lot about how this tool could be used for landscape classifications. According to the training and the toolbox website OTB provides a number a number of functionalities such as:
- image access: optimized read/write access for most of remote sensing image formats, meta-data access, visualization;
- standard remote sensing preprocessing: radiometric corrections, orthorectification;
- filtering: blurring, denoising, enhancement;
- feature extraction: interest points, alignments, lines;
- image segmentation: region growing, watershed, level sets, mean-shift;
- classification: K-means, SVM, Markov random fields;
- change detection;
- information extraction for integration in GIS and mapping systems.
Working with GIS is an art of compromise. It is more often than not a compromise between the limitations of your tool and your task – not to mention the operators capacities. As GIS practitioners we are used with seeking our solutions using commercial software like ArcMap, ENVI and many other. We have all appreciated the tools provided by commercial providers. Open Source tools are now advancing fast.
We have now come to where QGIS is able to deliver solutions which we only two years ago could not imagine. Advanced remote sensing data analysis is available for download. Combined with plugins and tools like the ones mentioned above this will provide GIS practitioners with additions or alternatives to what is currently in their toolboxes.
Using open source software is not only a matter of handling costs. It is more complex and an issue which deserves a separate article. For more thoughts on open source software in the development cooperation I would suggest an earlier article on this website.
QGIS is a solid framework. Yes it still crashes – more often than once in a while. But so does ArcGIS 🙂