Posts by TerraLab

Photogrammetry rebuilds a surface from overlapping photos. LiDAR measures it with a laser. One gives colour and a cheap flight, the other sees under the trees.

Multispectral records 4 to 13 wide bands, hyperspectral 100 to 300 narrow ones. A table of bands, free satellites, drone sensor cost and data size.

A plot plan draws one lot, a site plan the whole project. The 8 items 19 US permit checklists ask for, who can draw a plot plan, and how to make one in QGIS.

An orthophoto is one corrected photo; an orthomosaic stitches many. How each is made, why one drew Berlin's TV tower 127 m off, and 7 free national services.

Semantic segmentation labels every pixel with a class: building or not. Instance segmentation draws every building as its own object.

How to use AI Agent in QGIS: install it, write your first request, stay in control, then 5 real tasks, from open data to an HTML report.

A greenfield site was never built on; a brownfield site was, and may hold slabs or pollution. What each costs, how it looks from the air, 314 sites counted.

Browser panel > XYZ Tiles > double-click OpenStreetMap. Then satellite tiles by URL, QuickMapServices, a national WMS, and the ground size of each zoom.

A DSM is the top of everything, a DTM bare ground, a DEM either. On one town tile the DSM made 41% of the ground steeper than 30°, the DTM 7%. 8 free sources.

Flat, watercolor, pencil and glossy, all rendered from one aerial image of Letchworth Garden City. Every prompt in full, and where the model invented water.