Posts by TerraLab

Check OpenStreetMap first. Then four ways to map rooftop PV from aerial imagery in QGIS, with the menu paths and where each one fails.

Start with QuickOSM on leisure=swimming_pool. Where the map is thin, use a segmentation model, threshold the blue, or run a water index. Five methods compared.

Start with QuickOSM: in four French towns OSM held 96 to 98% of paved road length. Where it is thin, five more methods and the line-or-surface choice.

For multispectral imagery, threshold NDVI in the raster calculator, then polygonize. Six methods, what each one needs, and what a canopy layer costs.

Load imagery in QGIS, draw a zone, and get a georeferenced four-class site plan back in under a minute. The manual route, the AI route, and where each breaks.

Five ways to show a street rebuilt, from hand-drawn vector layers to a generated aerial view. Only one gives back a picture that stays on the map.

From the official hazard map to a generated aerial view of the water. Which method gives a number, which gives a picture, why an elevation model changes both.

The ground area inside a building's outer walls: what counts, how to calculate it, 8,511 houses measured, and why Microsoft's footprints run 19 to 31% too big.

For a classified raster, use Raster > Conversion > Polygonize. Here are the five methods, the fix for staircase edges, and what to do with a photograph.

GeoAI is machine learning run on geographic data. The five things it extracts today, what it costs in hardware and time, and how to run it in QGIS.