Geoprocessing

Provincial Spatial Data Cleaning

Clipping open DEM rasters in QGIS and calculating slope angles to see where rugged terrain funnels large carnivores.

Alberta wildfire point data in WGS 1984 — Figure 1: Comparison of Alberta wildfire incident points in raw geographic coordinates (WGS 1984) on the left versus reprojected into the provincial planar grid (NAD 1983 10TM AEP Forest) on the right.

Alberta wildfire point data reprojected to NAD 1983 10TM AEP Forest — Figure 1: Comparison of Alberta wildfire incident points in raw geographic coordinates (WGS 1984) on the left versus reprojected into the provincial planar grid (NAD 1983 10TM AEP Forest) on the right.

1. The Problem with Raw Data

Free spatial data downloaded from open provincial portals is almost never ready to map immediately. Road networks often have duplicate segments, forestry cutblocks frequently have overlapping boundaries or invalid geometries, and coordinate reference systems are not always the same across files from two different government sources.

2. The Cleaning Protocol

Before running any distance checks or buffer zones, every layer goes through three basic steps in QGIS: reprojecting everything into standard BC Albers (EPSG:3005), checking and fixing invalid polygon geometry to prevent topology errors during overlays, and filtering out unneeded attribute columns so project files stay fast and manageable.

3. The Takeaway

If the foundational spatial layers have small errors, every habitat corridor or road density calculation built on top of them will be flawed. Setting up clean, verified layers from the start saves hours of troubleshooting down the line.