Hi,
I'm kind of a veteran, I'm one of the developers of TG2 :-).
Anyway, I'm afraid that I haven't had any luck finding a way to crop out your area of interest. On Windows I tried dlgv32 Pro which is kind of a version of Global Mapper. It looks like you can do what you want with it but not with a free version. I also tried Landserf which is a Java app. It could export the data but only one small corner of it. I think this might be because I convinced the developer some years ago that the maximum size for the terrain in a TER file was 4097! I'm not really an expert on this so others might be able to help. The data is in a widely accepted format so that's not a problem.
FWIW you will probably be able to open the data in v2.5. I can open it with a test version, it can handle the data no problem. You do need to mess with it a bit to get it correctly scaled. I was able to massage the data into a form you can use. I didn't crop out anything, it's the whole South Island. It's also not ideal because I made the sea level have an altitude of 0, so that kind of means the land blends smoothly into a flat area of sea. Anyway, you can download it here if you want to try it out:
http://www.jomeder.com/downloads/South_Island.exr.zipIt's about 17 MB.
The file is an OpenEXR file. To use it do this:
- Go to the Terrain project view and click the "Add Terrain" button.
- Choose "Heightfield (load file)" from the menu.
- In the Open dialog change the file type to "All files" and navigate to the OpenEXR file. Open the file.
- When TG2 has loaded the file you will need to adjust it a little to make it the right size. Make sure the Heightfield Load node which was just created is selected in the Terrain project view list.
- Click the Add Operator button below the list and choose "Heightfield resize".
- In the Heightfield resize node make sure "Re-size in metres" is checked.
- In the first text field for "Re-size in metres" enter 700600.
- In the second field enter 843400.
- Now the heightfield should be the right size, pretty much.
The two steps where you enter numbers are resizing the terrain to the correct size. OpenEXR is an image format and doesn't hold any information scaling. By default TG2 will treat a pixel as being 1m wide so I multiplied the pixel dimensions by 100m because that's the resolution of the data.
You could actually crop this image in Photoshop or some other image editor which supports OpenEXR. You would then load the cropped EXR just like above but in the Heightfield resize node you would enter the cropped image dimensions multiplied by 100.
It's actually pretty good data, considering it's 100m resolution. I've attached an quick test render with the camera kind of at the top of Southland looking north.
Regards,
Jo
