If the image includes all of the planet's surface features, then, technically, there is no need to resize the texture. Even though it looks squashed horizontally when you look at it by itself with an image viewer, it will be properly stretched when Celestia projects it onto the planet. Its vertical resolution will be twice its horizontal resolution, of course, but that's not necessarily a bad thing.
If the image does not include all of the surface features, then you need to use image manipulation software to add the topography that is missing.
The Map functions in Iris are best used to convert between different types of map projections, not to resize or concatenate images.
I usually use ImageMagick's convert utility to resize images. This command will create an 8Kx4K output image from any size of input image:
Code: Select all
convert -geometry 8192x4096! input.jpg output.jpg
I usually use NetPBM's utility pnmcat to concatenate images. ImageMagick can do it too.
