We are pleased to announce that Mappt now supports ArcGIS Compact Cache Bundles.
Loading in your own satellite imagery is a common feature request for Mappt and it’s not hard to see why. Accessing your own imagery from a tablet gives GIS professionals and field workers the unprecedented power of being able to stand inside their data and perform ground surveys and analysis with total confidence they are looking at the correct features. The inclusion of Compact Cache bundles is one of several new features that allows loading of custom imagery into Mappt and at the time of writing we are the only option outside of ESRI to utilize this format. Mappt has been tested on the Sony XPeria Z with 30Gb of imagery and we have found the only limitation is the amount of free space on the SD card.
Compact Cache Bundles are a convenient format for tiled Imagery. The biggest advantage of compact caches over an exploded format is that it eliminates the overhead associated with thousands of little files which means faster file transfer times and less space on disk. This is a huge deal when transferring several Gigabytes worth of imagery onto a tablet.
Behind the scenes compact cache bundles act like a phone book.
Up to 16,000 tiles for a particular level of detail are conglomerated into a single file with a .bundle extension. This file has a companion with a .bundlx extension that acts like an address book for tiles. Looking up the address for a tile has some computational overhead compared to an exploded format but fortunately we were able to optimize it to the point where there is no impact on Mappt’s performance.