About CoolingSpots

• The cooler a place, the bigger and darker its marker - the three levels match the legend.
• The symbol in the marker shows the type of place: conifer for forest, broadleaf trees for park, waves for swimming spots and pools, plus dedicated symbols for waterfall, gorge, cave, highland (mountain) and cemetery (flower).
• Tapping a marker opens the details with the coolness reasons - including directions and sharing.
• Getting there: as soon as you share your position, the place sheet shows the straight-line distance, the direction and - from 100 metres of difference upwards - how much higher or lower the place lies. Straight line means: the real route is always longer. We do not show travel times, because we do not compute routes.

The score is arithmetic on open data: counting pixels, computing distances and angles. No trained model. Caves are the exception.

• Scored places: forests, parks, cemeteries, swimming spots, waterfalls, gorges, caves and highlands from OpenStreetMap. Areas count from 5 ha, cemeteries from 2 ha, each as one point. A forest or park only appears with evidence of coolness: tree canopy from 40%, terrain shade, water in immediate proximity, a nearby glacier, or an elevation from 2000 m. Swimming spots and caves always appear.
• Tree canopy: ESA WorldCover, a free land-cover map in which every 10 m pixel carries a class (tree, grass, cropland, built-up). Tree pixels are counted in a window of 21 by 21 pixels around the place: 380 out of 441 gives a canopy of 0.86. The grid is defined in degrees; the window measures about 195 m north-south and, depending on latitude, 110 to 160 m east-west.
• Water: distance to the nearest stream or lake (OpenStreetMap), searched up to 500 m. The effect halves roughly every 100 m.
• Terrain: elevation from the Copernicus elevation model. The value rises linearly from 300 m and is full from 1500 m. Air cools by about 6.5 degrees per 1000 m of elevation.
• Built-up area: share of residential, commercial and industrial land (OpenStreetMap) within 200 m. Built-up surfaces store heat and lower the score.
• Terrain shade: if a place lies markedly lower than its surroundings (eight directions within a 500 m radius, from the elevation model) or on a north-facing slope, that counts towards the same shade factor as tree canopy. Treeless places such as gorges and north slopes thus reach a coolness level.
• Glacier: ice less than 2 km away adds up to 10%, decreasing with distance.
• Caves: a fixed value instead of a measurement. The rock conducts the annual mean of the surface inwards. On a hot day cave air sits far below that - further than canopy or water ever reach. Hence level 3. The base value is 72 out of 100, plus elevation, because the annual mean falls with altitude. Source: karst research on heat conduction in rock (Dominguez-Villar and others, 2023). At the entrance the temperature varies with the weather.

Score = 40% shade + 30% water + 20% terrain - 20% built-up, plus a glacier bonus of up to 10%. Levels follow fixed thresholds: from 66 out of 100 level 3, from 48 level 2, below that level 1. Fixed thresholds mean a level says the same thing everywhere, including the lowlands. The badge "Cooler than its surroundings" marks places cooler than most within roughly 12 km.

Limits: the levels are an ordinal comparison, not a thermometer, so no degree values are given. The zero point of the scale is an open, low-lying place with no canopy, no terrain shade and no water nearby; built-up ground subtracts further. What is meant is the benefit on hot days: in mild weather the difference is small, because little solar radiation is being blocked. Places near a threshold can fall on either side. The value describes the typical, naturally occurring coolness of an area from static data, not the shade at a given hour. The surroundings are measured in a window of roughly 130 to 200 m, so the statement is regional rather than street-level. Above the tree line, sparse mountain forest can be overestimated. Intermittent and seasonal watercourses are excluded, because small streams carry little water in dry periods. A narrow gorge is shaded by day but traps heat at night - daytime coolness is what is meant.