I wanted to let you know currently there is not option or tool from within ArcReader, which would allow you to determine the azimuth for a dataset. This would be because ArcReader is designed to be a viewer of published/packaged data, and not intended to make edits to the dataset. This would be what would need to happen to the dataset in order to determine the azimuth of a dataset. I would suggest posting this on our Ideas site, for possibly a button to be added, to determine the azimuth for a dataset. Gracias!