Infos pratiques

Frequently asked questions


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Who is behind TherMap ?
TherMap is a private initiative of Dr. Beda Sigrist, a senior Swiss glider pilot with a background in engineering, computing, and industrial optimization. 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, along the ideas of TherMap. With the primary advice of Olivier Liechti, the initiator of Regtherm and Toptherm, the encouragement of OSTIV, particularly of Hermann Trimmel, as well as the positive response of numerous experienced glider pilots, he pursued the development of TherMap up to the present version. The Flying Club of Gruyère, Switzerland, has been hosting the site from the beginning.

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. 10), 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 latest evolution, the extention 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?
No, it cannot. It might of course be interesting to make available the source code used to generate the maps. The developments are however likely to continue. If the source code was distributed, the product would have to be wrapped up as a professional package and update management procedures introduced to ensure that the users would always have available the latest version. The resulting costs would require a costly commercial approach. Apart from the much bigger effort, this would be in conflict with the conditions set by SRTM, the distributor of the satellite data, which is basically only made available for non-commercial 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, such as the infrared characteristics of the surface, may some day also become freely available and permit to develop valid solutions 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. On the other hand we have 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 colleages it would however be a pleasure to extend the scope of TherMap to further suitable regions.

Can the maps also be used by paragliders?
In principle yes, but due to their slower speed and lower gliding ratio, paragliders are more limited in the use they can make of the maps. 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 strongly determined by the preferred paraglider take-off locations, hence leaving out many interesting areas known by glider pilots and shown on TherMap.


Société d'aviation de la Gruyère S.A. CH-1663 Epagny Tél:++41.(0)26.921.00.40 / Fax:++41.(0)26.921.00.44