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Building TerraGear: Difference between revisions
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== Introduction == | == Introduction == | ||
The terrain used in [http://flightgear.org FlightGear] -- the land over which one flies, its texturing (by land usage type), the rivers and lakes and so forth -- are generated by software from a sister project called [http://terragear.org TerraGear]. TerraGear is used to read in geographical data -- descriptions of ground elevations, land cover (usage) information, airport locations and layouts, and so forth -- and output terrain over which one can fly. | The terrain used in [http://flightgear.org FlightGear] -- the land over which one flies, its texturing (by land usage type), the rivers and lakes and so forth -- are generated by software from a sister project called [http://terragear.org TerraGear]. TerraGear is used to read in geographical data -- descriptions of ground elevations, land cover (usage) information, airport locations and layouts, and so forth -- and output terrain over which one can fly [http://www.courseworkhelp.org/ coursework help]. | ||
For a variety of reasons, you might want to build terrain yourself, rather than downloading it from the available scenery on FlightGear. For instance, if you use [http://taxidraw.sourceforge.net/ TaxiDraw] to modify/improve information about an airport's taxiway/apron layout, you might wish to see how that modified airport would look in the scenery before deciding you're happy with the results. And normally to see and use the airport in the scenery, it's necessary to [http://www.x-plane.org/home/robinp/#Updates submit the changes to Robin Peel], have him sign off on the changes, have the changes appear in the next [http://www.x-plane.org/home/robinp/ official apt.dat], and then wait for the next [http://www.flightgear.org/Downloads/scenery.html official FlightGear scenery] build; if you can build terrain yourself, you can start using it right away. Maybe the official scenery is too detailed for your slow machine, and you'd like to build terrain using a digital elevation model (DEM) with poorer resolution, to decrease the number of polygons and thus improve your framerates. Or maybe you've got a fantastically fast machine, and you want to build your own terrain using higher-resultion vector data (vmap1, Tiger) to get better roads/streams. For all these reasons, learning how to use TerraGear is a good idea. | For a variety of reasons, you might want to build terrain yourself, rather than downloading it from the available scenery on FlightGear. For instance, if you use [http://taxidraw.sourceforge.net/ TaxiDraw] to modify/improve information about an airport's taxiway/apron layout, you might wish to see how that modified airport would look in the scenery before deciding you're happy with the results. And normally to see and use the airport in the scenery, it's necessary to [http://www.x-plane.org/home/robinp/#Updates submit the changes to Robin Peel], have him sign off on the changes, have the changes appear in the next [http://www.x-plane.org/home/robinp/ official apt.dat], and then wait for the next [http://www.flightgear.org/Downloads/scenery.html official FlightGear scenery] build; if you can build terrain yourself, you can start using it right away. Maybe the official scenery is too detailed for your slow machine, and you'd like to build terrain using a digital elevation model (DEM) with poorer resolution, to decrease the number of polygons and thus improve your framerates. Or maybe you've got a fantastically fast machine, and you want to build your own terrain using higher-resultion vector data (vmap1, Tiger) to get better roads/streams. For all these reasons, learning how to use TerraGear is a good idea. | ||
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There's existing documentation for TerraGear in at least three places: in the source code tree when you fetch it, on the website, and [http://cvs.terragear.org/cgi-bin/viewcvs/viewcvs.cgi/*checkout*/www/docs/scenery-tutorial/fg-scenery-tutorial.html?rev=1.3&cvsroot=TerraGear-0.0 in the CVS tree for the website]. The latter is the most current, and really needs to replace the version on the website; but all three are out of date in various ways. When I tried to use the most current documentation to use TerraGear, I ran into all sorts of problems: some I figured out on my own, and others various people helped me with (thanks especially Ralf and Frederic). I'm writing this stuff to detail what I had to do to use TerraGear to build scenery. I am not trying to rewrite the documentation; this should be considered an adjunct/supplement to the TerraGear docs, something you read along with the TerraGear docs. The docs can steer you wrong, or miss something; this is my effort to address those issues. | There's existing documentation for TerraGear in at least three places: in the source code tree when you fetch it, on the website, and [http://cvs.terragear.org/cgi-bin/viewcvs/viewcvs.cgi/*checkout*/www/docs/scenery-tutorial/fg-scenery-tutorial.html?rev=1.3&cvsroot=TerraGear-0.0 in the CVS tree for the website]. The latter is the most current, and really needs to replace the version on the website; but all three are out of date in various ways. When I tried to use the most current documentation to use TerraGear, I ran into all sorts of problems: some I figured out on my own, and others various people helped me with (thanks especially Ralf and Frederic). I'm writing this stuff to detail what I had to do to use TerraGear to build scenery. I am not trying to rewrite the documentation; this should be considered an adjunct/supplement to the TerraGear docs, something you read along with the TerraGear docs. The docs can steer you wrong, or miss something; this is my effort to address those issues. | ||
So here I'll describe what you have to do to get TerraGear up and running; a separate page details [[ Using Terragear |how to use TerraGear]] to build the terrain for a particular area. A word of caution, however: I use Linux, so this description will be Linux-centric. I hope instructions for other OSes will be similar, but I really don't know. In particular, I don't have easy access to a Windows machine, so I don't know how what I say will differ for those on Windows. In fact, I don't even know if TerraGear can be built/used on Windows. Hopefully it'll work, under directions not too different from here. If not, hopefully someone else will edit this page to clarify how to do it (if it's possible). | So here I'll describe what you have to do to get TerraGear up and running; a separate page details [[ Using Terragear |how to use TerraGear]] to build the terrain for a particular area. A word of caution, however: I use Linux, so this description will be Linux-centric. I hope instructions for other OSes will be similar, but I really don't know. In particular, I don't have easy access to a Windows machine, so I don't know how what I say will differ for those on Windows. In fact, I don't even know if TerraGear can be built/used on Windows. Hopefully it'll work, under directions not too different from here. If not, hopefully someone else will edit this page to clarify how to do it (if it's possible). | ||
== Building TerraGear == | == Building TerraGear == | ||