First steps using GIS

Changes in river and forest habitats in the Göta river catchment, Sweden

The objective of this work was to start manipulating data by creating new shapefiles (editing) and getting acquainted with digitizing (tracing forms from other maps). To that end, I had to show how the Klara river in the Göta river catchment, Sweden changed between 1965 and 1992, and how forest logging practices have changed in a particular area close to the river.

The analysis of the river was based on georeferenced aerial photographs from 1965 and 1992. I had to digitize the channel banks and all sand bars/islands for both years. Next was to measure the width of the river channel at predefined monitoring sites for both years as well as the make-up of the features around each site. Logging the results in a table, I could graphically present what changes have occurred.

In hindsight, I should have included the locations of the monitoring sites in the final map to better indicate where exactly the river has been changing.

Compiled shares of all features found at each monitoring station, showing that riparian vegetation increased between 1965 and 1992, while sand bars/islands and agricultural fields diminished.

As with the river, the analysis of the forest was based on georeferenced aerial photographs from 1965 and 1992. I digitized the areas that were clearly forested, and areas that were clearly logged. The result showed that between 1965 and 1992, forest cover in the entire area of interest (0.97km2) increased from 0.43km2 (44%) forest cover in 1965 to 0.95km2 (98%) forest cover - an increase of 121% in the 27-year timeframe.

Digging deeper, in his report Forestry legislation in Sweden, Jan-Erik Nylund (2009) suggests that this favorable development can be explained by the changes in forestry policies and regulations that took place in Sweden in the 20th Century. Specifically how the middle of the 20th century was characterized by profit motives and deregulation, while after the 1970s, this had shifted more towards a focus on sustainability practices, regardless of ownership.