In this case the Local scale values happen to be the same for both X and Y. We use it to tell Manifold how the coordinate numbers in the imported component should be interpreted. The Edit - Assign Projection dialog comes into play when we import images from formats, such as ordinary TIF, that do not store projection information. To georegister the image, we click on the info bar and then use these values in the Edit - Assign Projection dialog. If the image is 4096 pixels high and the height of the image is 180 degrees we know likewise that the local scale in the Y (height, North - South) direction is: In the on-line manual -> index -> cookie cutter there is an example explaining how to accompich this: If the image is 8192 pixels wide and the width of the image is 360 degrees (which it must be to cover the entire Earth in Latitude / Longitude projection) we know that the local scale in the X (width, East - West) direction is:
It should be enough to just assign the appropriate projection. I believe the blue marble images of the whole world at nasa website are in lat/lon so you don't really have to georegister them using control points.
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