Multi Criteria Overlay Analysis
Following a tutorial, I identified suitable areas for development which are far from water, near to roads and not in a protected region.
Tutorial: Multi Criteria Overlay Analysis (QGIS3) — QGIS Tutorials and Tips
Automating Map Creation with Print Layout Atlas
Following a tutorial, I created a wetlands map for each county in the state of Hawaii with the print layout Atlas.
Tutorial: Automating Map Creation with Print Layout Atlas (QGIS3) — QGIS Tutorials and Tips
Batch processing
Following a tutorial, I took several global vector layers and clipped them to the extent of Africa in a single batch command. I also merged the clipped layers into a single Geopackage file.
Tutorial: Batch Processing using Processing Framework (QGIS3) — QGIS Tutorials and Tips
Using The Processing Modeler
Following a tutorial, I created a processing model to produce a density map by aggregating points over a global hexagonal grid.
Tutorial: Automating Complex Workflows using Processing Modeler (QGIS3) — QGIS Tutorials and Tips
Interpolating point data
Following a tutorial, I used a point layer of depth measurements taken by a depth sounder at a lake to create an elevation relief map and contours.
Change in Built-up Area in the City of Johannesburg Metropolitan Municipality (2014-2018)
This map was begun by following a tutorial, then extended. The tutorial was to use a change assessment dataset to identify urban growth patterns in the city of Johannesburg from 2014 to 2018. Once done, I added OSM features including major highways and rails. I calculated the raster area for the 3 classes and added a pie chart. Finally, I designed the print layout.
Handling invalid geometries
Following a tutorial, I fixed a geometry error in a state boundary layer. While attempting to run the ‘topological coloring’ algorithm, I encountered an error. I ran vector geometry>check validity to find the root cause. There was a ring self-intersection, which happens when a geometry touches itself and generates a ring. I used the vertex tool to edit the layer and fixed the geometry.
Handling Invalid Geometries (QGIS3) — QGIS Tutorials and Tips
Creating heatmaps
Following a tutorial, I worked with a dataset of crime locations in Surrey, UK and created a heatmap to visualize regions with high density of crime. I created a new attribute with a higher value for violent crimes, in order to give violent crimes relatively more weight in the heatmap.
Tutorial: Creating Heatmaps (QGIS3) — QGIS Tutorials and Tips
Calculating raster area
Following a tutorial, I used a raster layer with land cover classes and calculated the area of each class within a national park.
Tutorial: Calculating Raster Area (QGIS3) — QGIS Tutorials and Tips
Sampling raster data
Using a raster grid of daily maximum temperature and also a US counties shapefile, I calculated the average value within each polygon using the zonal statistics tool. The result is a thematic map which shows US counties by maximum daily temperature.
Tutorial: Sampling Raster Data using Points or Polygons (QGIS3) — QGIS Tutorials and Tips