I have created an index to use with data drive pages. I used strip map index and then altered the geometry of the index polygons to better fit my project area. I also added additional index polygons. As a result I copied the geometry of the polygons and created a new index shapefile. In this new shapefile I populated the attribute table with labeling along with before and after label (since some of the maps are sequential for match lines).
I now need to add a field which calculates the data frame rotation for each polygon. Strip Map index does this automatically, but under the circumstances, I need to do this semi manually. How do I populate an attribute field with the data frame rotation angle?