Is it possible to change the page orientation of a map using data driven pages in ArcGIS 10.1? After setting up the DDP I have 80 portrait maps with all the map elements set up correctly. About 10 of the maps actually need to be in landscape, but with all the same elements, so when I am exporting them, I would like to be able to indicate that those 10 should be generated in landscape.
You will need to set up two map documents, one for portrait and one for landscape. Your index layer will need a field to store the page orientation, something like "Pagesize". Then use the definition query on your index layer to limit which features will be included in that set of maps, e.g., [Pagesize]="85x11P" or [PageSize]="85x11L".
It's pretty straightforward, but you will need to set up two separate map documents.