Howto:Create custom terrain

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Revision as of 06:46, 15 November 2009 by Gijs (Talk | contribs) (Updating & Extending the howto, more to come)

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See history for the latest developments.

Look here an example of the achievable result.

Let's take a look at the Finistère in Brittany, Western France: if you click [1], you will quickly see and understand how the Finistère county is know of FlightGear. Some towns/city (red), a few forests (green), etc. Overall, it is not a very good resolution: a lot of angles, the detail level is not that good, some towns are missing. If you want a better definition on ground, there is some work to be done! The goal being to obtain something like this:

  1. Berlin
  2. Bodensee surroundings
  3. Oshkosh surroundings
  4. Carribs

You will immediately notice the improvement to the ground. When flying, the difference is huge. Moreover, this enables the autogeneration of cities, trees, farmland, and so on.

Downloading the Landsat pictures

Landsat Map Search
Preview and download Landsat image

Browse to the Earth Science Data Interface interface to grab your Landsat data.

  1. Click Map Search.
  2. Click ETM+ (left column).
  3. Click on Update Map on the right bottom of the map.
  4. Click on the Placetab on the upper side of the map, in order to do a search by place, or you can do a search by latitude/longitude.
  5. In the Place field, type Brest, France for instance.
  6. Check that you have 2 images in selection for example : this confirms that your selection is good. For Brest, there are two Landsat pictures to cover the area.
  7. Click on Preview and download. You will get the screen shown on the right. On the left you can check the picture you are going to download. The size of the pictures is also given.
  8. Click on Download to get a FTP access.
  9. Only the files with a .tif.gz and .met extensions are of interest.
  10. Uncompress the .tif.gz files in the directory of your choice.

Working with QGIS

QGIS with the TIFF image.
Creating the class column.

Using a GIS software gives you the opportunity to realize a full range of interesting operations: modification of VMAP data, updates on the ground classification, etc...

  • If you run GNU/Linux, you can install QGIS with your usual package repositery manager; see here. The process is easy and not described here, but it is one the QGIS website.
  • If you are running Windows, download QGIS from here (Windows - Standalone).
  1. Launch QGIS.
  2. Click on Layer > Add a Raster layer.
  3. Modify the filter to search for *.tif files.
  4. Add the TIFF file you have just downloaded.
  5. Click on Layer > Add a new vector layer or on the corresponding icon. A dialog should pop up.
    • Make sure the file type is an ESRI Shapefile.
    • Make sure the vector type is set to polygon.
    • You need to create a data column for this layer. Create a column called 'class'. Make sure it is a string column. Add it to the attribute list by selecting the Add Values Manually button. The 'OK' button should now be available for you to select. Select 'OK'.
    • There should be a dialog box prompting you to save your vector layer. Save it in your scenery directory with your GeoTIFF. (This is not required but significantly helps organization.)
    • A projection box should pop up. Select 'WGS 1984'. After all, that is the globe model used in FlightGear.
  6. Your vector layer should appear in the left-hand toolbar. You are ready to begin digitizing.
  1. Switch to the edition mode.

External links