TerraGearBuild your first scenery tile
One ordered route from an empty directory to terrain you can load in FlightGear, replacing a README, a how-to from 1999 and six wiki pages that disagree.
Guides
The first five are written to be read in order. If you are starting from nothing, begin with Build your first scenery tile and work down. The rest are reference pages for individual tools, what each one reads, writes and gets wrong.
Where to get terrain data
Working download locations for the three inputs a TerraGear build needs, elevation, airports and land cover, with every link checked in August 2026.
Hardware and build times
Measured wall clock, peak memory and disk for one degree TerraGear builds, why land cover multiplies all three, and what the README’s days or weeks means.
Common errors and fixes
Seven real failures from building TerraGear and running it end to end, each with the exact output it printed, what causes it, and what fixes it.
TerraGear and the alternatives
How TerraGear relates to the TerraGear GUI and Scenery Designer, and the nine places the project’s own documentation contradicts itself about the three.
tg-construct
What the final TerraGear stage costs in time and memory, why land cover multiplies both, and the arguments that decide what the terrain ends up being.
genapts
The airport stage fails in two ways that look like something else, one like slowness and one like success. Both measured, with the flags that avoid them.
hgtchop and terrafit
How TerraGear reduces 12,967,201 SRTM elevation samples to 15,828 mesh nodes, which parts survive that cut, and the two commands that carry it out.
ogr-decode
A worked land cover decode from OpenStreetMap, the –spat flag that hangs a build without printing an error, and what adding land cover really costs.
A second square, and the area types it needed
A second one degree build in farmland instead of coastline, what it took to map its land cover honestly, and where tg-construct really spends its time.
Rendering FlightGear headless
A working recipe for rendering FlightGear with no GPU and no display, using Docker, Xvfb and Mesa llvmpipe, plus the two things that silently stop it.
The files a build writes
The four formats a TerraGear build writes, the BTG header layout including version 10, and how to check your output parses before FlightGear rejects it.
The apt.dat airport file
What is inside apt.dat, the row codes TerraGear actually reads, how the format is shared with X-Plane, and how old the copy FlightGear ships really is.
Windows and macOS
TerraGear has no native Windows or macOS build and no installer. Docker is the route that works, this is the recipe, and this is what it costs you.