Satellite Mapping.

[Kelburn]

I know I've asked this before but I haven't got a solid response.
Does anyone know how to lay satellite pictures in FS like Robin does in his God Zone and real NZ scenery?

[toprob]

This is done using the Resample.exe tool which comes with the SDK.

[G-HEVN]

SBuilder or SBuilderX has a nice, easy to use interface for doing it.

[Kelburn]

Robin, are there any easy to read tutorials to get me started on resample?

[toprob]

QUOTE(Kelburn @ Oct 2 2007, 10:06 AM) <{POST_SNAPBACK}>

Robin, are there any easy to read tutorials to get me started on resample?

Resample is the easy part. Although it seems complicated, that's only because does a number of different jobs, when using it for photoreal there's only one way to go.
The tricky part is sourcing, scaling and placing the image. If you already have an image source, then I could help you get started. However I will point out that I couldn't do this type of work without a small investment in some tools (approx NZ$400). I guess you could do the same thing for free, but the way I do it isn't:)

To get started, here's a quick look at an .INF file which is passed to Resample:

[Source]
Type = CUSTOM
SourceDir = "C:\Documents and Settings\XXXX\My Documents\makescenery"
SourceFile = "g41rotated.bmp"
Lat = -44.807787
Lon = 169.205609
NumOfCellsPerLine = 8043
NumOfLines = 6893
CellXdimensionDeg = 0.00006093385552654212
CellYdimensionDeg = 0.00004319236907007106
[Destination]
DestDir = "C:\Documents and Settings\XXXX\My Documents\makescenery"
DestBaseFileName = "g41rotated"
UseSourceDimensions = 1
[Source]
Type = CUSTOM
SourceDir = "C:\Documents and Settings\XXXX\My Documents\makescenery"
SourceFile = "g41water.bmp"
Lat = -44.807787
Lon = 169.205609
NumOfCellsPerLine = 8043
NumOfLines = 6893
CellXdimensionDeg = 0.00006093385552654212
CellYdimensionDeg = 0.00004319236907007106
[Destination]
DestDir = "C:\Documents and Settings\XXXX\My Documents\makescenery"
DestBaseFileName = "g41water"
UseSourceDimensions = 1
withseasons = 1
season = summer;alpha


This creates a simple summer-only scenery with a watermask. You could use this same framework for any similar job, the real trouble is when you get to the bit which says:
Lat = -44.807787
Lon = 169.205609
NumOfCellsPerLine = 8043
NumOfLines = 6893
CellXdimensionDeg = 0.00006093385552654212
CellYdimensionDeg = 0.00004319236907007106

Determining what these values are is a bit tricky. You can use a Resample 'Front-end', such as Terrabuilder, to do this. I'd certainly recommend this if you are not a mathematical genius. (I am, but I still use Terrabuilder...)

Let me know what sort of image you have, and I'll see if I can help.

[Kelburn]

Google Earth images around Melbourne and other Australian locations and using

http://www.linz.govt.nz/core/topography/ae...ndex/index.html

or

http://www.linz.govt.nz/core/topography/ae...nztm/index.html

for NZ locations.

If you could give me a sort of step by step way to lay a selection of these in FS I would really appreciate it.

[toprob]

Ok, I can give a quick intro to the LINZ imagery, because that's all I use. The main issue with LINZ images is that the projection is either NZMG (prior to 2004) or NZTM, and they need to be reprojected to WGS84, which is what the simulator expects. There are some tools around to do this, I used to have a list, but I never really found anything free which did the job properly (i.e. without blurring the image). Maybe someone could suggest some useful tools for this. In the end I bought Global Mapper. At the time the latest version was US$249, from memory, but they were selling an older version for US$199. I'm now about 4 versions behind, but it does all I need it to do.
By the way, back in the old days I did this reprojection manually -- rotated the image by a best-guess figure, and tweaked the corners a bit -- I did this with Tauranga. This was not all that accurate, as you can imagine. Although it worked ok, when I redid the image for FSX it was obvious that I was a good 20 metres out.
Basically what I'm saying is that you'll need to figure out how to reproject the images yourself, unless you want to buy Global Mapper:) I suggest a good session with google to find something useful.
Once you have your reprojected image, you'll need to crop it a bit. That's because when it is reprojected there's a degree of rotation, which adds blank corners to the image. For FSX this isn't a problem -- you can use the whole image -- but with FS2004 you'll need to get rid of these corners. This is another reason why you'd need a good GIS tool, and you'd preferably want to have some way to read the lattitude and longitude of your new cropped image, otherwise you're stuck with a guess.
So now you've got an image, reprojected and cropped, and you know the lattitude of the corners, you just need to rescale it so that is matched the fixed FS2004 resolution of 4.8 metres per pixel. Resample.exe will actually 'resample' it for you, but it doesn't allow any control over the image quality. I prefer to rescale it myself in my own image processing application. That way I can tweak the sharpness a bit. It's also easier to tweak the colour and retouch the image once it's been scaled down, as it isn't as hard on system resources as the larger image.
To rescale it, I actually cheat a bit -- I load the image into Terrabuilder Lite, enter the coordinates of the four corners, then use the resulting resolution reported by Terrabuilder to compute the change in X and Y scales. For example, if Terrabuilder reports the X scale as 2.417492, then I divide this by 4.8 which gives 0.5036 roughly, allowing me to rescale the image in the X dimension by this amount. However because of the way that the images are projected, the horizontal and vertical scale will differ, so you'll need to do the sum for both.
After I have a rescale percentage for X and Y, I can rescale the image in my imaging software, sharpen it, fix the colour (LINZ images are too blue) and fix any problems such as clouds etc.
I then use this image to mask the water, which gives me a 2-bit mask (although I need to save this as 24bit for Terrabuilder) -- white for land, black for water.
I then load up Terrabuilder, enter the image name and the water mask name, tell it the South West corner, and let it run. It creates the multitude of tiles which make up the photoreal scenery, and the .BGL which displays it.

[Kelburn]

just a quick clarification what does WGS84 mean?
Also what do you mean by reproject?

And do you not actually use resample to make the scenery but instead Terrabuild?

[toprob]

There are a lot of different ways that folk map the world. WGS84 is just one of them, but this is the projection which MS chose for the sim. You can have a read about WGS84 here.
In New Zealand we have out own mapping convention, which changed earlier this decade from NZMG (New Zealand Map Grid) to NZTM (New Zealand Transverse Marcator). To 'reproject' means to change from one mapping convention to another. There's a cute article on NZTM on the LINZ site -- in PDF format. The cute bit is on page 2 -- 'Conversion between Ellipsoidal and Grid Coordinates'. Note the conversion formula:)

Terrabuilder is simply a front-end for Resample.exe. This is explained on the Terrabuilder site. Unfortunately the site is tricky to bookmark, because it's in Flash, but navigate to the Help: FAQ section.