Ranges 8 allows background images but the alignment implementation is very basic. It insists only on two coordinates, the top right and bottom left corners of the image, which is not enough to allow for all the possible distortions: rotation, shear, scale, and translation. This can be handled by applying an affine transform to the image and for this we need four coordinates.
Ranges 9 gathers these coordinates with a clever new interface. The user loads the image and it is displayed with four markers defining the points on the image. He moves the markers by dragging them into a position on the image that he know the real world coordinate of, then enters these coordinates into the panel against the marker.
|The image alignment dialog|
Users can drag to scroll and select areas to zoom as well as panning and zooming with the familiar controls, just as they can with the new graphics screen.
|Zoomed in to the second alignment marker|
|The image as background for an edge file|