Is there any way to only cache tiles from a tiled basemap that are within a certain definable area such as an envelope or a polygon? I am specifically attempting to download http://tiledbasemaps.arcgis.com/arcgis/rest/services/World_Street_Map/MapServer for offline uses however, the basemap has somewhere near 47 billion tiles which far exceeds the cap of 100000. This being said my initial thought is to draw a rectangle around the users device position and only download the tiles that are within that bounded area. Is this feasible, or do I need to find another way to do this?
For those interested I am using xamarin for VS 2015 to write the app and this is the framework I am using to download the map: https://gist.github.com/anstrevor/90a202d8c1e587ad0803e053b33a73f9