Hey, why don't we retreive terrain data automatically from Google Earth? It would almost always be the most accurate terrain availiable, and these days it even includes buildings, etc...

For the very, very simple reason that FlightGear is an open-source project released under the GPL, whereas the Google data is copyrighted.

Retrieving terrian data from a proprietary internet source wouldn't violate the GPL. It doesn't violate the GPL when I view the google website from the open source firefox....

Oh, I get it, I forgot to specify. I mean that we could retrieve data from the google earth servers, not from the google earth executable, which _would_ violate the GPL.

this is a very interesting idea...do you know the way to get it from the servers?and do you know which dataformat they have?

It would probably be somewhat difficult, as they wouldn't want to let a competitor's program connect to their servers. It would probably be encrypted, and in some sort of hard to use format. The plus side is that they couldn't significantly change anything on their end without messing up all of their client applications. Anyway, the idea of a Google Earth flight simulator occurred to me when I first saw Earth running, but I'm involved in a huge Computer Science project already; it is my last semester in college.

FlightGear's source of terrain is accurate, so there is no need to use Google Earth. Beside, Google Earth and its data are proprietary, so we can't include it into FlightGear.

It might be accurate in terms of terrain, but the Google terrain is unquestionable better in that all images are actual sattellite images of the ground. Flightgear's source of terrain is nowhere close. Also, using Google's proprietary data does _not_ violate the GPL. Using proprietary code would, but this is just data. Firefox, an open source browser, routinly shows proprietary data from the google website, doesn't it?

> It might be accurate in terms of terrain, but the Google>terrain is unquestionable better in that all images are actual>sattellite images of the ground. Flightgear's source of>terrain is nowhere close.For your information, FlightGear uses NASA's SRTM data with 3 arc seconds resolution. I don't know what Google's source of terrain is, but given the fact that Google Earth is not intended to be a Flight Simulator, you can bet that its resolution of terrain is too low to be used in FlightGear.As to satellite imageries, we made a point not to use them. Directly from our project leader:**********First off don't get me wrong, I'm not trying to shoot down the idea of satellite imagery overlayed on terrain. But each approach has it's strengths and weaknesses. Typically when you pick an approach you try to find ways to minimize or eliminate the weak elements, or else convince yourself that you don't care or don't need the missing/problematic stuff. That's certainly true with the current FG approach to scenery, and is true with satellite based imagery as well. Here are a couple disadvantages that come to mind - The imagery is frozen, one point in time. This means that vehicles, shadows, season, time, date, are all frozen in your imagery. You can get stuck with goofy things ... for instance we have a demo of the San Jose airport done at about 1 ft = 1 pixel resolution. It's beautiful, but there is a 737 taking off that is frozen in the picture ... as well as other aircraft frozen in various states of taxiing or being parked. You can consider editing these things out on a case by case basis, but it's very difficult to fix all these sorts of problems on a global scale. - Shadows. I'm repeating my first point, but it's important with terrain. Depending on time of day and season, the shading of terrain can totally change and be illuminated from one side, or the complete opposite side at a differnent time of day. With satellite based scenery, you have to live with the world looking like whatever time of day the imagery was taken. - It's very difficult to exactly match the imagery up with your terrain elevation data. Again, you can tweak manually here and there, but it's really difficult to get a perfect match, and very time consuming to do this on any sort of large scale. - The resulting imagery is of course 2d ... so tall buildings, towers, trees, etc. are all just flat images in the picture. This looks great from above 5-10k feet, but as you get close to the ground (i.e. on landing or take off) the whole effect goes to crap and you get a big blurry pixel mush. - You can add 3d objects to the world to help fix some of these problems, but you can never get past the weird notion of a 3d building or tower sitting on top of a slanted 2d picture of itself ... with an odd shadow in the wrong place for the curren time of day. - Satellite imagery is by it's nature a mosaic of zillions of little images often pieced together from different dates and times to filter out cloud cover and other oddities. But that means that in terms of color, brightness, shadows, etc. you can never get perfect matches between the individual pictures. This can lead to odd artifacts in the resulting scenery. - It's huge ... satellite imagery to cover the planet consumes a huge amount of disk space. And as you fly and have to page it in and out, you have to do a ton of disk and memory I/O at the same time you are trying to keep your frame rates smooth and glitch free. That can be problematic, especially on typical consumer level PC's. Depending on what you want, none of these things have to be show stoppers, but after you get past the initial "WOW" factor of satellite based scenery and start interacting with it, you begin to see all kinds of different areas where it is lacking ... sometimes very annoyingly so.**********Personally, I would rather see roads and buildings modelled into the scenery than using satellite images.> Also, using Google's proprietary data does _not_ violate>the GPL. Using proprietary code would, but this is just data.>Firefox, an open source browser, routinly shows proprietary>data from the google website, doesn't it?Data from Google Earth is not free. It is copyright Google and we can't redistribute it.Given your interest in improving the scenery in FlightGear, what you could do is join TerraGear's mailing list and start contributing your work there. TerraGear is FlightGear's terrain generation engine, and it is something that needs to be improved upon. However, very few people are interested in working on it. You work will be valuable there. However, PLEASE drop the Google Earth issue, as it will never be considered.

Viewing their imagery in a web browser is fine.However using the imagery in another product is NOT allowed!From their "Terms and Conditions" page :Photographic ImageryThe photographic imagery made available for display through Google maps is provided under a nonexclusive, non-transferable license for use only by you. You may not use the imagery in any commercial or business environment or for any commercial or business purposes for yourself or any third parties.You may not copy, reverse engineer, decompile, disassemble, translate, modify or make derivative works of the imagery, in whole or in part. You also may not rent, disclose, publish, sell, assign, lease, sublicense, market, or transfer the imagery or any part thereof or use it in any manner not expressly authorized by this agreement.By using Google Maps, you do not receive any, and Google and/or its licensors (if any) retain all ownership rights in the imagery. The imagery is copyrighted and may not be copied, even if modified or merged with other data or software.Unless the imagery is public domain or licensed under GPL it cannot be used.Paul

if people are reallllly hooked one the idea of sat imagery, forget google. google is private property.so you may think, where do we get free sat imagery?try World Wind, by NASA, all imagery is public domain. do a google search. not quite as good as google, but this is mainly due to it not being paid for etc etc.....

Hello all-Guess what - I am a :-newbie, and I like smilies . . . Just a few comments in response to this thread in general and on a couple of specific points . . .Regarding access to google imagery- yes, they bought it, and no, you can't have it . . . :-violinRegarding satellite imagery - well, it should be mentioned that there are several types of satellite imagery, and the most common versions (Landsat7 variations) are not of high enough resolution to really see most buildings - however, the 15 meter/pixel and even the 30m Landsat 7 visible color datasets are really quite nice for general terrain viewing, etc. and they actually 'drape' quite well over srtm (elevation data) layers. This brings me to my next point -NASA WorldWind is an open source global viewer/GIS (it has a ways to go on full GIS functionality, but it is coming along) which utilizes free and open data - this means that anything you see in WW can be utilized in any application you choose - in fact, Flight Gear uses the very same elevation data as WW (SRTM 30 for US, SRTM 90 globally). Most of the imagery displayed in WorldWind comes from NASA or the USGS - NASA provides several variations of global Landsat imagery, while the USGS (via TerraServer) provides DOQ (Digital ortho quads -black&white 1 meter resolution) and topographic maps for essentially the entire lower 48, and much of Alaska and Hawaii - plus higher resolution color aerial orthos for selected US cities (ranging from 1 meter to .3meter resolution/pixel). Work is ongoing in the WW community to locate and access other free sources of imagery, notably the high resolution ortho images everybody loves so much. Google has spent (and continues to spend) large sums of money for their 'eyecandy,' and those imagesets are offlimits, except on very specific and limited terms. The WorldWind project cannot do this :-( , BUT . . .Just to address the comment on Google Earth being 'better,' it really depends on what you wish to accomplish. Personally, I believe there is little comparison, with WorldWind being significantly superior in most aspects, excepting GE's eye-candy and some nice usability features such as their KML scripting. Incidentally, I wrote the bulk of a wiki topic on this where I gave GE perhaps more credit than I truly felt it deserved, but it presents a fair coverage of the differences between the two programs (for starters, WW is open source and has lots of scientific applications, which in the near future are going to get even more powerful, amazing, and even user-friendly). Read that at WorldWind Central http://www.worldwindcentral.com/wiki/Google_Earth_comparison (note that upcoming versions of WW have some significant surprises in store, among them being GML support and an expansion of the currently basic shapefile support- there is also some effort underway to get WW ported to a X platform code base, but that is still some months away, and will probably not occur until after the release of the next major release, which is expected early 2006 and will be a complete restructure/major code rewrite of WW )And so, finally, I get to my point . . . :-rollWorldWind has a very nice plug-in interface, allowing users to write their own functionality into the program- the plugins may be included as text files, which are compiled by the program at run time. So what does that have to do with anything, and how is this my point? Hold on - I'm getting there . . .Some months ago, the developer who brought us the plugin feature wrote a plugin apparently in response to a request made by Flight Gear developers. This plugin allows the WorldWind camera to be controlled remotely via udp. For the WWC add-on page for the plugin, visit http://www.worldwindcentral.com/wiki/Add-o...er_%28plugin%29For the developer's posting on his weblog (http://www.mashiharu.com/) about the plugin, and to access others, visit http://www.mashiharu.com/archives/2005/06/...04T12_02_00.txtIMPORTANT DISCLAIMER :-hangSo far as what the status of this is regarding Flight Gear, I really couldn't say - perhaps some readers will know better. Also, I would request that people do not bother the developer with questions regarding this unless they are in the position to actually accomplish something by it and they have FIRST done their homework (this doesn't mean just reading a FAQ page, either). :-bang Mashi is a very busy man, and he has lots of people asking for his support as it is- he wrote the plugin as an example to WW users, and in response to a specific request by Flight Gear developers. Please direct questions to the FG team first! Thank you (and sorry, FG devs) :-)