Frequently asked questions


What has triggered the idea behind TherMap?
Many birds find their best updrafts using inbuilt rules honed over millions of years of evolution. Compared to this, statistical maps based on actual flight tracks tend to show thermal hotspots along "trodden paths", typically in the vicinity of gliding airfields, usually neglecting basic conditions such as the time of the year or the daytime. On the other hand physical models permitting to identify thermal hotspots considering these basic conditions are bound to be very complex and require a lot of computer power to simulate results.

Our idea was therefore to try a computerized model using simple empirical rules derived from descriptions of experienced pilots, and to then validate and refine them by comparing the results with actual glider flight logs available on OLC. After about two years of trial and error research, the computed thermal maps started to become more and more realistic and to arouse the attention of renown glider pilots and meteorologists of OSTIV. Their encouragement finally led to the publication of the the model in the OSTIV Journal. On the occasion of the opening of the Gliding World Championships 2008 at Lüsse/Berlin, Germany, OSTIV considered TherMap to be " a quantum leap in analyzing and optimizing flight paths in known and unknown orographies".

Who is behind TherMap ?
In 2004 Beda Sigrist, a senior Swiss glider pilot with a background in computer modelling, was intrigued by the fact that the vast knowledge of experienced pilots had never been translated into a computer model permitting to show the thermal hotspots on a map. Impressed by the precision of the regional meteorological forecasting tools of RegTherm and TopTherm, he started to investigate the possibilities of making use of presently available topographic data. With the help of descriptions, particularly of Jochen von Kalckreuth, the primary advice of Olivier Liechti (Initiator of Regtherm and Toptherm), the encouragement of OSTIV, particularly of Hermann Trimmel, as well as the positive response of many other experienced glider pilots, he pursued the development of TherMap up to the present version.

The feedback by pilots and experts has permitted to continuously improve the model and to update this site with still better maps. In this respect particular thanks go to Alfred Ultsch, for his additional validations on the basis of flightlogs, his publication of the findings (ref. 9), and for his pertinent improvement proposals. Further thanks go to Iakov Shrage, a top competition glider pilot besides 21500 hours as an airline pilot, who encouraged the extension of this site to also cover the region of Slovakia. The further evolution, the extension to US regions down to 35 degrees latitude, with very high sun elevations during summer months, became possible thanks to the initiative and practical advice of Sergio Colasevic. This step also required further developments to make the maps more readable.

Can the application behind TherMap be purchased?
It might of course be interesting to make available the source code used to generate the maps. The developments do however continue. If the source code was distributed, the product would have to be wrapped up as a professional package with regular updating procedures, to ensure that the users would always dispose of the latest version. This would however result in a costly commercial approach requiring considerable resources. In addition it would also be in conflict with the conditions set by SRTM, the distributor of the satellite data, which is basically only made available for noncommercial use.

What possibilities exist to use the TherMap model for topographically smoother regions ?
This is a question we continue to ask ourselves. With the introduction of the thermal pressure model it became possible to produce maps for regions outside the higher mountains, such as the Jura. In topographically still less pronounced regions the local variations of the surface becomes smaller and more scattered, making it more difficult to identify topographically induced thermal takeoff areas. In addition the flight level above ground are usually higher than in mountain areas, making it also more difficult to validate possible thermal models on the basis of flight track data. However thermals always have a physical cause. It may therefore be possible that other than orographic causes may some day be identified and used to produce similar maps for flatter regions.

What possibilities exist to generate TherMap images reflecting the actual local meteorological conditions at a given time?
This question can probably only be answered in the longer term. In Europe diagrams showing the hourly meteorological evolution are available for regions of 50 to 100 kilometers. On this basis in would, in principle, be possible to generate corresponding TherMap presentations. The data would however have to be paid, because it would have to be supplied for automatic processing. In addition there would also be the costs of daily processing. Finally one has to keep in mind that the actual demand for such highly detailed maps would be rather marginal.

Can TherMap be extended to other region?
The development of TherMap has also been the result of intensive information exchange with experts and experienced pilots, because the models represent only partly physical processes, the other parts being rather models of the perception of experienced pilots. For any new region to be addressed it is therefore crucial to have competent and experienced counterparts to properly adjust and validate the models, if necessary. With pertinent help of local colleagues it would however be a pleasure to extend the scope of TherMap to further suitable regions.

Can the maps also be used by paragliders?
The publications of the TherMap maps has also been well received by the paragliding community. Due to their slower speed and lower gliding ratio, paragliders are more interested in the hotspots within more limited regions. In countries such as Switzerland, paragliding "highway" maps have been successfully established on the basis of statistical analyses of flight logs. Therefore the resulting routes are more determined by the preferred paraglider takeoff locations, hence leaving out many interesting areas known by glider pilots and shown on TherMap.