Heat Map and Heat Register: What They Show and How They Are Created

In short. A heat map shows spatially where your urban area heats up particularly strongly. A heat register is the systematic, often continuously updated collection of this information for the entire municipality. Both are derived from climate models, satellite and geodata, and information on development and land use. Their value lies not in the map itself but in the fact that they make measures justifiable and comparable.

Why this matters for your municipality. Without spatial data, heat measures are often implemented where they are visible, not where they are most beneficial. A heat map shifts the discussion from gut feeling to evidence. It is also a solid basis for funding applications and for communication with the council.

What exactly does a heat map show?

This depends on the type of map. Common distinctions are: surface temperature (from satellite data, showing the heat of roofs, streets, greenery), air temperature or thermal load (closer to human perception), and nocturnal heat load. Health outcomes often depend on the night. It is important to know the type of map: the surface temperature of a roof says little about the strain on the people beneath it.

How is such a map created?

Several data sources form the basis: satellite data for surface temperatures, DWD climate and weather models, geodata on buildings, sealed surfaces and vegetation, and, where available, local measurements. These layers are combined to create a comprehensive picture of heat exposure. The level of detail ranges from coarse grid resolution to maps at neighbourhood or building level. The finer the detail, the more complex the data.

What do municipalities use a heat register for?

Three typical uses:

• Prioritisation, where should limited funds be used first?
• Linking with land use, where does high exposure coincide with vulnerable facilities?
• Impact monitoring, does exposure change after measures are implemented?

A register is continuously updated so that you can track developments over the years.

The honest limitation. A heat map is a model, not a measurement at every street corner. Resolution and data quality determine its informative value. A coarse map shows trends but does not replace detailed on-site assessment. And the map alone changes nothing, it is a basis for decisions, not a measure.

When KomAdapt is worthwhile. If you want not just a map but a usable analysis, KomAdapt's risk and exposure analysis combines heat data with your concrete urban structure and vulnerable uses, as was done for the heat maps for the town of Meinerzhagen. This turns coloured areas into a well-founded order of priorities for measures.

_What is the difference between a heat map and a heat register?_ A heat map is a single representation of heat exposure. A heat register is the systematic, usually continuously updated collection of such information for the entire urban area, often linked with further data. _What data sources underlie a heat map?_ Typical sources are satellite data for surface temperatures, DWD climate and model data, geodata on development, sealed surfaces and vegetation, and sometimes local measurements. _How accurate are heat maps?_ Accuracy depends on resolution and data quality. Coarse maps reliably show which districts are relatively warmer. Statements for a single address require finer data. _Do small municipalities need a heat register?_ Even small municipalities benefit from a spatial overview. The effort can be scaled to need, often a map of the warmest areas linked with vulnerable facilities is sufficient to start.

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