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TherMap© version 2.0 - released Feb. 2011

On August 6, 2008, on the occasion of the Opening of the Gliding World Championships at Lüsse/Berlin, Germany, OSTIV awarded Dr. Beda Sigrist a diploma for this innovation, considered the work to be " a quantum leap in analizing and optimizing flight paths in known and unknown orographies". The utilization of these maps for non-commercial purposes remains free. For commercial uses, quotations, as well for further publication written copyright permission must be obtained via the mail address mentioned at the end of this site, and this site quoted as the source.

Thermal Maps for
Mountain Regions

For ridge wind maps see WindMap

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Introduction:
Background:
Access Maps:

Welcome

Position the cursor on the picture below and you can see a map extract of TherMap, a tool for glider pilots, to visualize the local potential of thermals on digital maps on a given date and hour, assuming favorable meteorological conditions. For any sensible time and date of interest, thermal hotspot maps can be downloaded from this site free of charge.

A second possibility is to directly overlay the maps on Google Earth, which offers further viewing facilities such as 3D perspectives or flight simulations visualizing the thermal hotspots. Finally, a complet set of the country maps can be ordered on a DVD at a cost covering charge, covering Switzerland, Austria, the French Alps, the Pyrenees, the Northern and Central Apennine, Slovakia, as well as the American Sierra Nevada between 35 and 43 degrees latitude.

Unlike other thermal maps, which are usually based on statistical analyses of flight paths, thus essentially just showing "trodden flight paths", the maps of TherMap have been derived solely from the orography ( cf. model outline). The maps therefore also show the potential of thermals in less known territory.

Before the flights TherMap maps permits to study the best itineraries, or to explain them to less experienced pilots, particularly across less known regions. After the flight, flight logs (typically IGC-files converted to KML for use with Google Earth) may be superimposed to these maps, to find out where more promising paths might have been followed.

What is new in TherMap 2.0 ?
To make the maps easier to read and to facilitate the orientation, TherMap 2.0 shows areas with lower thermal potential only as topographic backdrop surfaces. In relatively flat areas, where the TherMap model can provide little guidance, significant elevations within a radius of about 1 mile are now highlighted by an "x" mark, as those could be an additional hotspot locations. Following a request of Sergio Colacevich, a well-known American glider pilot, the 420'000km2 region of the US Sierra Nevada has been added to the menu. For the time being, the previous maps of TherMap 1.06 can however still be accessed via a crosslink in the download section.

In January 2012 the surface of the US Sierra Nevada region was extended to the Pacific coast. To access the extended region on Google Earth you must ractivate the corresponding kmz-links by pressing here.

Following requests, special guidelines have further been added describing

  1. How to open OLC flight tracks in SeeYou and view them on a raster map of TherMap
  2. How to open OLC flight tracks in Google Earth and view them on a overlay map of TherMap

Using the Maps

a. How to read the maps
b. Flight preparation
c. Reviewing flights
d. Limitations of TherMap approach

a. How to read the maps

  • Zooming: The maps should be zoomed at least to 100 percent. Original maps may contain about 10 Mb in JPG format, which corresponds to about 30 standard screens. The maps are worthwhile to be studied in detail, if necessary by zooming above 100 percent, due to their huge information content. For your convenience it is recommended to use viewers (e.g. MS Picture Manager®) permitting to maintain the zooming level and the selected window frame while paging between different downloaded images.
  • Colour coding: The colours of the temperature and the irradiance maps vary from green to yellow and finally red. Assuming a glider with a minimum sinking rate of 0.5 m/sec the colours represent approximately the expected climbing rates shown on the following graph:


    Green areas, e.g. in relatively flat regions or at the end of the day, can still indicate how to best stretch a flight path, whereas during peak hours in mountain areas une can basically focus on the red colours only.
  • 3D visualisation: Using the Google link below, linking TherMap with Google Earth® takes only seconds, whereas importing them for instance in SeeYou® (as raster maps) is more complicated and takes several minutes. A further advantage of Google is that "flight" routes can be simulated, which is useful for flight preparations. For flight reviews, which can be useful to study alternative flight paths, several free conversion programs can be found on the Internet to convert IGC flight record files into KML files. Upon clicking on these files they open with Google Earth®.

b. Flight preparation

  • Meteorology: TherMap supposes a calculated solar irradiance and a non-stable atmosphere responding to temperature increases. It is therefore only usable on sunny days with good meteorological conditions, i.e. en unstable temperature gradient and sufficiently high condensation base. In other words, TherMap is a complementary tool to meteorological forecasts, but can in no way replace these. It is up to each pilot to learn and determine, when the conditions are suitable to make use of TherMap. In case of predominant winds it may further be worthwhile to consult WindMap.
  • Checking planned flight paths: TherMap is best used before the flight to check the local conditions at the expected time of overflight (e.g. when to change to the other side of a valley) and to note possible alternatives in case of unexpected changes.
  • In-flight use of TherMap: Consulting a map during the flight must not interfere with the necessary observation of the flight space. Tests with mobile navigation devices, into which TherMap hotspots had been imported, have shown that this represents a risky distraction from flight observation, further aggravated by the poor readability of present displays. However even with better displays, the mobile tools should be designed to automatically show the hotspots valid at the actual time, to avoid manual file manipulations distracting the pilot.

c. Reviewing flights

  • This requires the flight tracks to be traced on the maps closest to the date and time of the flight. Besides identifying possible alternative flight paths, such analyses also help to better interpret TherMap. Due to the ease of activating the maps on Google Earth, the latter tool is preferrable for such analyses, because it does not require importing (raster) maps into flight planning aplications. On the other hand, the latter tools offer the known additional features of these specialised tools.

    If needed, the following links open guidelines for making such analyses either with SeeYou or Google Earth


Colour coded thermal pressure map in 3D-view with vario-flighttrack
(reproduced using SeeYou© on the basis of an imported thermal pressure map)

d. Limitations of TherMap approach

  • Limitations of radar maps: Radar reflection signals are not perfectly precise when scanning altitudes (precision about 5m). They are particularly unreliable when reflected by water or ice. This it why it is difficult to automatically identify lakes on the basis of radar scan data. In TherMap many lake outlines have therefore been imported separately, but these imports had to be limited, due to the manual effort involved, and hence not all lakes are displayed. Some ice covered surfaces appear blurred. Fortunately neither of these limitations seems to limit the use of the maps.
  • Wind drift: The further away the glider is from the ground , the more its flight path may be shifted in the direction of the wind drift. Such shifts can be visible on TherMap flight tracks on a windy day.
  • Borders of plains: Air heated over plains can be shifted by slight wind until hitting a small edge or elevation, thereby triggering a thermal. At present TherMap does not map such locations.
  • Other effects: TherMap only shows the solar heating effect causing thermals on slopes. At certain locations other effects can however be stronger than the thermals, e.g. due to cloud covers, or wind, particularly at narrow valley entrances, but also where the air is cooled by lakes or ice covered surfaces.

Regions Available
Europe
Country/Region
North-West Corner
South-East Corner
Switzerland
48° 00'’ N / 05° 30’ E
45° 30'’ N / 11° 00’ E
Austria
48° 00'’ N / 09° 30’ E
46° 00'’ N / 16° 20’ E
French Alps
47° 30'’ N / 05° 00’ E
43° 00'’ N / 07° 30’ E
Pyrenees
43° 20'’ N / 03° 00’ W
42° 00'’ N / 02° 30’ E
Northern Apennine
45° 00'’ N / 07° 30’ E
43° 30'’ N / 12° 30’ E
Central Apennine
43° 30'’ N / 11° 30’ E
41° 00'’ N / 15° 00’ E
Slovakia
48° 00'’ N / 18° 00’ E
50° 00'’ N / 24° 00’ E

 

United States
Country/Region
North-West Corner
South-East Corner
US Sierra Nevada Very North
43° 00'’ N / 125° 00’ W
41° 00'’ N / 115° 00'’ W
US Sierra Nevada North
41° 00'’ N / 125° 00’ W
39° 00'’ N / 115° 00'’ W
US Sierra Nevada Center
39° 00'’ N / 123°30’ W
37° 00'’ N / 113°30'’ W
US Sierra Nevada South
37° 00'’ N / 122° 00’ W
35° 00'’ N / 112° 00'’ W

 

View/Download Maps

Country :

Depending on the flight you may have to select one or more of the countries or regions
Date : TherMap provides maps of selected dates from the beginning of April to the middle of September (Months 4 to 9). Select the maps showing the date closest to the flight date. The map date/time is included in its file name (month-day-hrZ)
Time:
UTC is now generally used, whereby 3 map times per day have been included in the map collection, namely one for the latest full hour before the highest elevation of the sun, and two others 3 and 6 hours later, respectively. If we tolerate that the map-time may differ up to 90 minutes from the flight, these three maps basically cover a total time interval of up to 9 hours.

UTC is normally also used in the flight records. Select the map closest to the time of overflight. A longer flight will therefore require several maps. This also applies to flight analyses, for which we recommend however to make use of the Google Earth overlays of TherMap.

The following table contains maps generated by TherMap2. The TherMap1 menu with the entirely colour coded maps is however still available.

Each of the OK fields of the following table represents a map of a region at a given date and time. Select the one closest to your flight path. (about 6-10 Mb per JPG map). Then either double click on the field of the map to be viewed, or right click on the target field and request the map to be saved directly on your PC.

The complementary maps either show the basic topography or the slope determined view of the region.

EUROPE
Time
UTC
Date
Complementary
maps
01.Apr
16.Apr
04.Mai
01.Jun
01.Jul
01.Aug
20.Aug
01.Sep
10.Sep
Switzerland
10h
13h
16h
France
Alps
11h
14h
17h
Austria
10h
13h
16h
Pyrenees
11h
14h
17h
Apennine
North
10h
13h
16h
Apennine
Center
10h
13h
16h
Slovakia
10h
13h
16h


USA
Time
UTC
Date
Complementary
maps
01.Apr
16.Apr
04.Mai
01.Jun
01.Jul
01.Aug
20.Aug
01.Sep
10.Sep
Very North
Sierra Nevada
19h
22h
25h
North
Sierra Nevada
19h
22h
25h
Central
Sierra Nevada
19h
22h
25h
South
Sierra Nevada
19h
22h
25h


All maps of this collection are provided by the copyright holder solely as an informational tool for the planning of the best course of soaring flights. In particular, airports and landing places are indicated mainly for geographical reference without guarantees about their exact location and/or their operational conditions. These maps are not intended to be used for navigation. Pilots should independently confirm all information regarding airports and landing places and other information required for navigation, and obtain an official briefing before flight. In no event shall the copyright holder or the contributors be liable for any direct or consequential damages caused by incorrect, obsolete or missing graphical or written content.

The copyright holder: Beda Sigrist, Switzerland

Viewing with Google Earth

A 3D view may facilitate the perception of a thermal landscape, as illustrated by this example. Users having installed Google Earth© on their computer can generate such perspectives themselves and/or simulate flights in a "landscape with visible thermals". In addition actual flight records (converted to KML file format) can be superimposed to review a flight.

TherMap is based on the same topographic data (SRTM) as Google Earth. It is possible to link TherMap files with Google Earth within seconds. Before doing this you should be aware of the following:

In order to avoid a significant loss in image resolution (due to a constraint of Google Earth), the original charts had to be cut into tiles of two square degrees which are therefore referred to at the lowest level of the Google selection tree. TherMap actuall had to generate almost 3000 tile files for this purpose. The resulting Google selection hierarchy looks as follows

(1) TherMap2-3D> (2) Region > (3) Region+date+daytime> (4) Tile (coordinates of left lower corner)

It is crucial to never select the maps above the level of the "Region + Date + Daytime"i.e. level 3. Above this level Google overlays all maps below the level selected, e.g. all dates and daytimes of a selected region, which would be meaningless. It is however also possible to activate several adjacent regions for a specific date and daytime. Note that loading the tiles still takes a few seconds with Google Earth.

Example of how to use Google Earth:
Suppose you want to see the area around Lake Mono (US) on June 1 at 19hUTC, click on the link below: "US Maps (Sierra Nevada)" and confirm that you want to open this link with Google Earth, upon which the Google screen appears.

  1. Under "Places" at left first click the "+" box to expand the map selection e.g. "TherMap2_USA-3D". You will see the regions available.
  2. Then click the "+" box of "SraNevd_C" (i.e. the Sierra Nevada beween 37 and 39 deg latitude).
    Google then shows the dates and daytimes available for this region.
  3. Check the empty square on the left of "SraNevd_CJun1_19hZ" to select all maps for this region ,date and time. Google then switches on the map tiles of this region and adds the list of these tiles.
  4. Unselect the tiles you do not need. In our case these are the ones ending with 37N117W, 38N117W, 37N115W, and 38N115W, leaving the four map tiles around Mono Lake. Then zoom into them...

Google overlay picture transparency is set at 20-35 percent, in order to still perceive the underlying Google landscape. The transparency can be changed manually at tile (= lowest) level by right-clicking on the selected flield, then clicking on "Properties" and finally adjusting the transparency slider on top of the property window.

Select Direct Link of TherMap2 to Google Earth:

Order a DVD of the Maps

Accessing the internet through high speed lines is not always possible. It may therefore sometimes be simpler to retrieve the maps directly from a DVD. The maps of TherMap2 can be delivered against pre-payment in Switzerland and the EU . For this purpose pls send TherMap an order by E-mail with the following indications:

      • name, surname, address and phone number of client,
      • precise mailing address if different from client address
      • the desired DVD: TherMap2

and make a pre-payment for the delivery

    • within Switzerland CHF 60.- to be paid to
      CCP 18-16534-8 (Beda Sigrist, ch. de la Mulla 42, 1616 Attalens) , or
      IBAN CH15 0900 0000 1801 6534 8
      Receiver: Sigrist Beda, CH 1616 Attalens)
      BIC (Swift Code): POFICHBEXXX
      Name of bank: Swiss Post, PostFinance, CH-3000 Bern
    • within Europe make a bank transfer of EUR 50.- per DVD at the intention of
      IBAN CH82 0900 0000 9126 4004 8
      Receiver: Sigrist Beda, CH 1616 Attalens)
      BIC (Swift Code): POFICHBEXXX
      Name of bank: Swiss Post, PostFinance, CH-3000 Bern

      *) Postfinance adheres to SEPA and should in principle receive bank transfers from other SEPA institutes at domestic tariffs.

Deliveries are made by ordinary mail as soon as the order and the pre-payment have arrived.

Links

  1. SRTM download website: http://srtm.csi.cgiar.org/
  4. MetPanel OSTIV 1 (2009): Weather Forecasting for Soaring Flight, World Meteorological Organisation (WMO)
  7. A website offering also wind maps: Meteoblue
  8. Meteorological panel of OSTIV
  10. Simulation von IGC-Flugfiles auf Google Earth,
    including IGC to KML conversion: http://ywtw.de/igcsimen.html
  11. Alfred Ultsch: "Thermikstrassenkarten", Segelfliegen 3/2010, Periodical Magazine
  12. Swiss thermal map for paragliders: http://thermik.kk7.ch
  13. B.Sigrist: "TherMap, el mapa térmico", Parapente vuelo libre, no. 81, 10 marzo 2011
  14. Sergio Colacevich: Sierra Nevada Great Basin TherMaps, Soaring, July 2011
Contact
If you have any comments, suggestions, or questions, you can directly contact the author Beda Sigrist by e-mail.

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
contact