I think flightman322 is actually trying to create 3D landscape since he stated
I know how to create a whole new airport, but I don't know how to use satellite imagery.
I've experimented with doing just this and here is the airport I created of Mt. St. Helens:
https://forums.realflight.com/downloads.php?do=file&id=14184
I can only tell you that if you want to create your own 3D landscape you are in for a huge uphill battle that won't be worth fighting really, but honestly I would like to see someone with the patience to pull it off, so I actually do encourage you to try if you have access to the 3D modeling software.
Before proceeding, you'll want to look up information on heightmaps. There is software out there which can use government led research data from LIDAR imaging, to create height maps. Along with the heightmap, you'll need to obtain the corresponding satellite images which can overlay the landscape. The satellite images and LIDAR imaging data base can be found on the net from USGS files. The tax payers paid for this research, so it can be found for free. However, you'll need to find software which can read these files and do everything you need it to do, which you may have to pay for.
The first thing to consider is in order to have proper ground handling which forms with every hill and crevasse, you'll need to keep the 3D model under 8,000 polys so that every miniscule point is collide-able. Since the size and form of the landscape will most likely be large, you'll end up with large polygons in places on the ground which are flatter than you would like, or hills and mountains not having the proportions you would like to achieve.
To counter this issue for larger maps, you could create several models which blend together at the seams and can be lined up like puzzle pieces on all sides. I figured out the rational behind the current Sierra Nevada maps flat drop off edges at all four sides of the map when I was trying to solve the issue of getting segments of land to match up at the proper heights on all sides.
They most likely used this technique of patch-working 3D map segments together and needed a means to control the start height level. This is my theory and I believe it holds up well.
The modeling part is actually very easy. You need say a 100x100 segment 2D plane to start with. Then you use a displace modifier to apply the heightmap to the 2D plane object. There are a few parameters to adjust and you basically hit a button and presto!--You have landscape. This is simplified a bit since I'm not at my home PC with reference material, but it's not anymore difficult really than how I describe.
The youtube videos most likely to assist you in understanding these concepts:
http://www.youtube.com/watch?v=sVskRIWVKns--applying displace modifier/applying heighmap in 3ds max (This is also the youtube video that taught me how to do it)
http://www.youtube.com/watch?v=EzUeAI0wLq0--creating a height map from height elevation data
Some search terms to assist you in reference material from the net:
terrain generation
terrain modeling
topological map
elevation data
Now after you have your model created, you have the real challenges ahead of you. If you have a LOT of images to piece together, it will take a LOT of computer processing power and memory to stitch the images together. For one, the size of the images will fill up a certain level of memory, but say if you have 500MB of images to stitch, 6GB of RAM might not necessarily be enough memory to handle processing the stitching operations required by the software without crashing the program or your PC. I can't remember all the details as to what all your PC has to do, but it uses a TON of memory.
Basically, it's easier to find an image that is already the area of land you require for your needs, or, use low resolution images.
The more difficult part of tyring to bring 3D landscape into Realflight is the fact, Realflight doesn't support user created landscape. You can work around that by bringing it in as an airport object, but you'll learn why that has so many draw backs. All objects and foliage you would like to add to the landscape has to be done manually and adjusted to the proper heights and if you are placing things at random elevations going up a couple thousand feet above see level, then you begin to see why this is such a pain. You have also spawn points to deal with, wind modeling since it will travel right through your airport object/landscape.
Aircraft ground handling is a major issue. Shadows I believe are also an issue, but maybe I just never had mine turned up to the highest absolute setting. Landing is difficult without shadows.
So, you can play with the airport of Mt. St. Helens I created and you can add airport objects and foliage to the ground. You can't add runways because the landscape is an airport object. Yeah there are lots of reasons why I never did anything more with landscape models for Realflight even though I would like to still, I just don't see it happening.
