What is shown on the thermal maps?
It shows the probability to find a usable ascending air current for a paraglider with the help of thermal trigger points. Each of the maps is optimized for a defined time period. No model data was used (only the flights).
What's a trigger point?
A thermal trigger point is a theoretical spot on the surface, where the heated air packages detach from the ground.

Wind shift in flyable heights is approximated linearly. A pilot has to be aware of winds in order to actually hit the thermal. Weather properties such as wind strength, cloud base, gradient of the air and so on depends on a given day, however trigger points (mostly) don't.
What about the weather?
Surprisingly the global weather conditions are of minor importance if one wants to find the thermal trigger point. However, weather is very important for paragliders but pilots mainly chose the area according to the conditions. Given a certain area, most flights are performed under very similar conditions and the positions of the trigger points is roughly the same. The wind component is limited as much as possible by reducing thermals to trigger points.
How good are thermal maps?
The main factor for good thermal maps is the flight density in a given area. It also showed that maps are generally better if the topology is the main thermal factor. In some regions, sparse thermal predictions are shown, where too few information is available. For example in the flatlands the prediction quality is generally lower, since there are fewer flights and most of them are performed according to clouds and not according to static triggers on the surface. Regions with too few knowledge are transparent in order to reduce clutter. Furthermore, thermals next to popular launch pads generally overrated (the position however is correct). This is caused by the fact, that most pilots only upload a flight if they at least catch the first thermal.
What do I need these maps for?
First of all, very good pilots which are familiar with a certain flight area, barely profit from the maps. But the maps proved to be good to study an unknown area: Where do I find my first thermal? Thermal probability is a good idea if no other signs for thermals are available. If one sees a beautiful cumuli, a climbing bird or even other climbing pilots, one has to blame himself if prefering to fly according to thermal maps. A second purpose is the analysis of performed flights (which is especially interesting in GoogleEarth) in order to optimize tactical decisions made in previous flights.
What are hotspots?
Hotspots are points where it is likely to find a thermal. They are extracted out of the raster based thermal maps. Again they are time dependent. Their main purpose is to be upload to a GPS in order to have them at hand right during flight.
How about soaring?
Soaring is filtered out wherever possible.
How were the maps created?
The initial trigger was my masters thesis, here available for download:
From this the following paper emerged (it's more technically oriented and less on paragliding):
But seriously; this is a lot of theory on sensor networking and such. But what really mattered to me was to create an open map database for every paragliding pilot out there and to provide simple tools to improve everyones flights.
Do note however, that in the time since this thesis was written the maps where heavily optimized and extended to new regions.
What about the rest of the world?
Generally is is possible to generate thermal maps for all regions of the world where the minimal conditions are fulfilled. However, it is currently technically limited since computational effort is very high. If you have access to a large number of flights (more than 10'000 igc's) for a region which is not yet mapped, please contact me.
Download
The recommended file format is
gpx. This fileformat can be uploaded to any common GPS device.
Hotspots are defined by position and height. The digits define the probability of finding a thermal in an area 250m near to the hotspot (as percentage). To make each name unique an optional .# is appended.
GPS Upload
There are various methods to upload the hotspots on a GPS device. Most manufacturers ship their proprietary software along with the device.
GPSBabel is an opensource alternative for all OS and GPS models.
Example command to upload gpx hotspots Garmin GPS:
gpsbabel -i gpx -f ./hotspots.gpx -o garmin -F /dev/ttyS0
Example
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An LK8000 OpenSource Flight Computer
with hotspots as airfields
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A simple Garmin eTrex
with (legacy) hotspots
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