Urban Heat Mapping

Satellite heat maps make urban heat visible street by street, and every one of them is a surface temperature at one moment of one clear day. In Madrid in July, dry grassland is the hottest surface at late morning, the city is 3 °C cooler than its countryside by day and 5 °C warmer by night, and its densest neighbourhoods have the coolest surfaces. These guides start with what land surface temperature is, the heat island, Landsat thermal data, emissivity, green space and heat exposure; then read Landsat surface temperature, build a summer composite, compute heat island intensity, relate heat to vegetation, parks, districts, air temperature, heatwaves and population — with the fixes for scale factors, clouds, the rural reference, scenes compared across dates and the resolution the pixels do not have.

Step eight is the one every later map is built on: the summer composite. It turns a dozen late mornings into one surface with its evidence count attached, and the fixes at the end are mostly about what a composite cannot do — compare dates, see through cloud, or resolve a street tree.