Demo 17 - Geoprocessing Tools (Part 1)

This QGIS tutorial introduces geoprocessing tools, which are used to overlay and combine layers based on their spatial distributions. These tools epitomize the power of geographic information systems and geospatial analysis. They enable the geometries and attributes of layers to be integrated for diverse applications, including assessing relative spatial distributions, proximities and relations between layers, as well as features and variables of interest. Follow along as we demonstrate these tools with a simple case study examining land-cover conditions around water features in southern Manitoba. The demonstrated tools include Buffer, Clip, Difference, Intersection and Merge, as well as Extract, Join and Select by Location. These tools can then be reapplied and iterated with multiple layers, enabling you to combine, analyze and visualize spatial relations between any variables, geometries and layers of thematic relevance to your area of expertise.
The classification guide and symbology file can be downloaded from the link below, for following along with the tutorial: github.com/Sta....
The tutorial also shows procedures for creating custom feature identifiers by combining attributes in separate fields with the concatenate and concat functions in the Field Calculator. These fields can then be applied to aggregate layers by feature attribute and geometry of interest. Stay tuned for the second part of this demo, where we will examine the total coverage of land-cover classes within the clip area, as well as variations by watershed. We’ll use the Statistics Panel and Statistics by Categories tools to verify values in our assessment and cover additional geoprocessing tools, such as Union and Symmetrical Difference.
Note: Not all tools in the demo are explicitly geoprocessing tools (e.g., Buffer, Dissolve, Aggregate), but most have common applications within geoprocessing workflows. For example, the Buffer tool is used in this demo to create the riparian area layer around water features prior to extracting land-cover conditions with the Intersection tool, while Dissolve and Aggregate can be applied to examine broader-level trends in geoprocessed layers.