Original version by Alexei Novikov Sep. 3, 1999 Updates by Curtis Olson Cliff description by James Hester 2018 Overview ======== The scenery creation process has 3 basic steps. 1. Fetch the raw data. 2. Preprocess this data into an intermediate form. 3. Assemble the intermediate data into the final scenery tiles. There are a couple basic types of data used to create scenery. 1. DEM data which is typically a set of elevation points on a regular grid. 2. Polygonal data such as landmass outlines, lakes, urban areas, glaciers, etc. 3. Other more specialized data such as airport runways and taxiways, lighthouse locations, etc. Preparation and Preprocessing ============================ 1) DEM data. As the first step you have to download DEM for the area you need. (You can get them from USGS site). Then you have to chop files that we got into the tiles used for the scenery generation. You should use hgtchop for this. As we already have a number of files I'm using the following Perl script #-------------------------------------------------------------------------- #!/usr/bin/perl my @files=glob("./*.hgt"); my $size=@files; for (my $i=0;$i<$size;$i++) { system("hgtchop $files[$i] /home/anovikov/w020n90/Work/SRTM-3"); } #-------------------------------------------------------------------------- Here you can change /home/anovikov/w020n90 to whatever you like but keep in mind that we will use that directory for our scenery generation. The 3 arcsec DEMs (which are available for the USA) should go in .../Work/DEM-3/ That's all with the DEM files. If yu want to have a blibloagraphy on them see f.e. http://www.geo.ed.ac.uk/geoinfo/dem.send 2) Airport Data Next thing is to generate airports data. You need to have default.apt from the fgfs-base package and genapts compiled. Usage is genapts /path/to/appt_file /work/dir (in our example genapts .../RawData/AirNa/default.apt.gz .../Work/Airports/ 3) Landmass Data You can just download it from Curtis FTP site ftp://kenai.me.umn.edu/pub/fgfs/RawData/Global-Landmass/ or generate it by yourself. If you download data from Curtis site then you should extract it in the .../Work/Global-Landmass If you are generating it by yourself you have to ask Curtis how he is doing that. 4) Landuse Data. (Curtis, you asked me for this). If you have a CD-ROM with DCW then you are lucky, if not you need to go to ESRI WWW site (http://www.esri.com/data/online/index.html), "Select by Geographic Area" - "Esri Thematic Data" (Go!) then Select a Theme - Natural Landscape Zones, Select a Region - Continent you need and download data. Please read the license agreement first. Then comes the tricky part. (You will need to modify the code) I included one file you have to change as an attachment . You have to put it in /FlightGear/Tools/Lib/Polygon/ rebuild the libPolygon and then change the shape-decode. Go to /FlightGear/Tools/Prep/ShapeFile/ open main.cxx and either comment out line # 357 or add || area == DefaultArea at line #279. Then you have to rebuild the shape-decode. Now we are ready to generate the landuse data. ./shapedecode /name/of_the_file_from_esri /work_dir/work.states (in my case it is ./shapedecode /users/anovikov/fgfs_data/aalandsc /home/anovikov/w020n90/work.states). 5) Hydro and Urban data. Origianlly I was using the same ESRI web server but this is kind of very tricky part that I will not tell you. (I was writing about the way to do it in the mailing list) I think that one can get data from Coastline Extractor using "Rivers from WDBII" but I'm not 100% sure. If you have acess to DCW then you just run shapedecode on the corresponding files puting hydro data in the directory work.hydro and urban data in the directory work.urban. As Curtis changed the directory structure in the last CVS versions you have to look in BuildTiles/Main/main.cxx first and modify the directory names accordingly. (FE 30 arc-sec files should be in work_base/DEM-30/ Now we finished with data preparation and we can start generating scenery but first we need to change the resolution of the data from the default values ( if we are working with 30 arc sec DEMs). You have to find line double error = 200.0 in Construct/Main/main.cxx and change initial error to smth like 10. Then you need to rebuild everything in that directory. I generally hate using tg-launch-clients and tg-launch-server so I'm doing everyting (almost) by hand. So I start from Construct/Parallel launch tg-construct-server on the computer with data on local disk and then slogin to other computers ( with data mounted over nfs) and run tg-construct-client in rude mode. After a while scenery is ready. That's all folks, Alexei. Addendum: Adding cliffs ======================= Cliffs represent discontinuities in the height array described above. This is problematic because: (1) Most height grids will give an average height in the area around the grid (2) Interpolation between grid points to get the local height will convert a cliff into a much more gentle slope. To add cliffs into the scenery using OpenStreetMap data, the following approach can be used: (1) Extract cliffs from the OSM datafile using your favourite tool, for example for all cliffs near Sydney, Australia: osmosis --read-pbf australia-latest.osm.pbf --bounding-box top=-33 left=150 bottom=-35 right=152 completeWays=yes --lp --tf accept-ways 'natural=cliff' --tf reject-relations --used-node --write-xml file='my_cliffs.osm' (2) Convert the XML above to Shapefiles: ogr2ogr -where "OGR_GEOMETRY='LineString'" -f 'ESRI shapefile' -lco SHPT=ARC cs_cliffs my_cliffs.osm (3) Run cliff-decode to place cliff information into the height grid working directory created previously (/cs_cliffs in the example below): cliff-decode /SRTM-3 /cs_cliffs (4) Optionally run rectify_height to fix grid heights. This is recommended as otherwise cliffs will have uneven edges and bases as the grid points vary in distance from the cliff: rectify_height --work-dir= --height-dir=SRTM-3 --min-lon=151.0 --max-lon=152.0 --min-lat=-34.0 --max-lat=-33.0 --min-dist=100 The min-dist parameter sets the distance from the cliff beyond which points are trustworthy. 100m is the default. (5) Place the cliffs into the scenery. This is identical to the process for rivers and roads and uses the same cliff information from step (2): ogr-decode --line-width 5 --area-type Rock /Cliffs /cs_cliffs" Note that an area-type of Cliffs will allow custom cliff texturing, if this effect is available. This command places a 5m wide strip of rock at the position of the cliffs. One side of this strip will have a calculated elevation at the top of the cliff, and the other will be at the bottom. (6) Run tg-construct as usual, including 'Rock' or 'Cliffs' polygon types to make sure that cliffs appear.