Data Coverage File
ArcView is a program used as a Geographical Information System with which you can analyse, create, manage and visualize geographical data.
Coverage files used by ArcView make use of the .adf file extension, these file consist of the mapping of one aspect of data in space, a good example of coverage data is the various data´s that make up a satellite image.
How to open .adf files?
Software to open .adf files
What are .adf files