Task 8 - Creating the Thermal Map

[ASH33M]

In this task we will create the thermal probability strength map, based on the sun exposure, forest maps and field maps.

The final bitmap must be in RGB format, but only the red channel is important so it's best to work with shades of grey, the white parts of the image represent good areas for thermals, black parts are bad areas for thermals.

The best places should be farm fields, cities and villages (70%), then grass and coniferous trees (40%), then deciduoud tess (20%), sea and lakes (5%).

Please note that the thermal map is automatically computed by Condor for mountain areas this will be in the new patch 9 when it's released, so it's only necessary to make thermal map for the flat areas (slope less than 1 degree).

Setp 1

Open your DeciduousMap bitmap.
Reduce the size of the bitmap by 50% (so the image size is equal to terrain mesh dimensions).
Set brightness to -100, contrast to +100, click ok.
Invert the image (so that deciduous forests are black)
Set brightness to -100, contrast to -80, click ok.
Set brightness to -30, click ok.

The resulting image should be 40% grey, deciduous forests should be 20% grey, you can check this with the eye dropper tool.

Step 2

Open your Fieldmap bitmap.
Reduce the size of the bitmap by 50% (so the image size is equal to the terrain mesh dimensions).
Set brightness to -100, contrast to +100, click ok.

Step 3

In this step we will mix the bitmaps from step 1 and step 2.

Copy the entire bitmap from step 2 to a new layer on top of the bitmap from step 1.
Select "lighten" as the blending option and set the "opacity" to 50.
Select Layer=>Flatten Image from the menu.

Test with the eyedropper tool to check if the fields are 70%, grass and coniferous trees 40% and deciduous forests 20%.

Step 4

At this stage, you may also want to add "very bad" areas for thermals, seas or lakes if your map contains them, usually, sea areas can be taken from the terrain mesh, you can also export the terrain mesh from the Landscape editor.

Open the CST Landscape editor and select your landscape from the menu.
Select Tools=>Export terrain to RAW format.
Write down the location of the RAW file and it's dimensions.
Open Photoshop, then select from the menu File=>Open then select the RAW file type.
Type the dimensions of the RAW file to the Width and Height input fields.
Select 16 bits and IBM OC, then click ok.
Set contrast to +100 and increase the brightness to get the appropriate sea mask towards a black colour.
Manually edit the resulting image to remove any noise.
This stage, you can also add any sea area or lakes, but this must be made manually as the lakes don't have 0 altitude.
Copy the bitmap to a new layer on top of the bitmap from step 3
Select "multiply" as the blending option.
Select from the menu Layer=>Flatten Image.
Using the Paint bucket tool, fill sea areas with 5% grey.

Step 5

Save the image to the following directory, Working\ThermalMap.bmp
This image must be 24 bit colour.

Step 6

Open the CST Landscape Editor and then select your scenery then select the thermal map option in the View/Modify list box to check if the bitmap loads correctly.

Step 7

Select from the menu File=>Export ThermalMap to export the bitmap into the LandscapeName.tdm file that's used by Condor to determine good or bad places for thermals and where they should be or not.

Step 8

Test in Condor by flying over good and bad areas for thermals.

[OXO]

Here are the starting values for the thermal probabilities. They can be adjusted a little, but in general the best areas for thermals should be 70%.

White 100%

• Desert 70%
  Fields 70%
  Towns,Cities,Villages 70-75%
  Bare rock 75%
  Grass 40%
  Coniferous trees 40%
  Deciduous trees 20%
  Water, Marsh, Swamp 5%
  Snow 5%

Black 0%

Within these values, you can adjust up or down a little. For example if you have a field pattern with some darker fields, it is possible to increase the dark fields to 75%. But if your field pattern is all dark fields, they should remain at 70%.

[grinvaldsjanis]

Hi! Is there a short answer for parameters if I export my thermal map BMP from QGIS.
Is it the same grid and what is the size of tiles in px. Slovenia terrain does not have any folder with thermal maps, so I can not get parameter from there.

[dgtfer]

Thermal map is not tiled, it is a 90m resolution map, in the .tdm file.
You could at least read the scenery creation guide, everything is carefully explained...

[OXO]

Thermal map is not tiled, it is a 90m resolution map, in the .tdm file.
You could at least read the scenery creation guide, everything is carefully explained...

.. and he could also not reply to posts from 2006

[grinvaldsjanis]

Thermal map is not tiled, it is a 90m resolution map, in the .tdm file.
You could at least read the scenery creation guide, everything is carefully explained...

I think You should read that document where it carefully tells how to properly export thermal map from QGIS in 90m resolution. I believe that author just felt that he explained it well to first-time scenery creator.

There should be some simple formula at least for resolution of an image if one has 12X9 tiles. Then it could be enough for me to make it.

Updated - I see that it should be 256 per tile...so 3072 x 2304. No it wasn't clearly explained.

[grinvaldsjanis]

Thermal map is not tiled, it is a 90m resolution map, in the .tdm file.
You could at least read the scenery creation guide, everything is carefully explained...

.. and he could also not reply to posts from 2006

which is the most recent topic/tutorial about thermal layer using qgis?

[EDB]

12×23040÷90=
9x23040÷90=