Tag: guide

We measured 307,225 French buildings: a story is 3.07 m (10.1 ft) at the median, and a 5-story building stands 16.2 m (53 ft) to the gutter.

Microsoft matched 25% of a French town's cadastre buildings, OpenStreetMap 83%. Then Nairobi: five free sources, timed downloads, checked on drone imagery.

KML is map data written as XML in WGS 84; a KMZ is the zipped form. How to open, edit and convert both, and why a KMZ saved in QGIS fell to 134 bytes.

NDVI flattens out over dense canopy. EVI, SAVI, NDRE, NDWI and NDMI each fix a blind spot. Raster Calculator formulas and a measured test in Brazil.

One French suburb at six pixel sizes. At 10 m, 0.2% of its buildings cover 16 pixels; at 50 cm, 96% do. Counts of 20,911 buildings and 2,966 pools.

Sentinel-2: 10 m pixels, 5-day revisit. Landsat 8 and 9: 30 m, a thermal band, an archive to 1972. Bands side by side, and clear views counted at three farms.

Can ChatGPT automate QGIS? I asked it for PyQGIS code on three real tasks and ran every script in QGIS. What worked, what failed without an error, and why.

A CRS tells software where coordinates sit on Earth. Datums, EPSG codes, 4326 vs 3857, and a step-by-step fix for a layer that lands in the wrong place.

NDVI measures how green and dense vegetation is, from red and near-infrared light. What the values mean, a season measured field by field, and QGIS steps.

QGIS is free, open-source software for making maps and working with geographic data. What it does, what QGIS 4 changed, and 3,600 plugins counted.