It looks like Apple has been busy quietly expanding the number of partners it uses for data for Apple Maps.
Greg Sterling at Screenwerk reports that Apple has a new copyright page that lists the partners, and that the list is roughly twice as long as the old list. He doesn't link to the actual page, but says these are the sources listed:
INCREMENT P CORP
MDA Information Systems, Inc.
Department of Natural Resources Canada
CGIAR Consortium for Spatial Information
Flickr Shapefiles Public Dataset
GeoNames and contributors
ESA 2010 and UCLouvain
National Aeronautics and Space Administration
(OSDM) © Commonwealth of Australia
U.S. Census Bureau
U.S. Department of State
U.S. Geological Survey
National Geospatial-intelligence Agency
Apple's Maps product was quite controversial when Apple switched to it and away from Google Maps. Complaints were rampant, and the company even had to issue an apology to users, but the complaints pretty much died down after Google Maps became available for iOS thanks to a new app from Google itself.
It's unclear how many of Apple's users are using Apple's product rather than Google's, but either way, it must be putting forth the effort to improve it. Of course, Google has been putting forth quite a bit of its own over the years, and now is even said to be close to acquiring Sklybox Imaging for nearly a billion dollars, which could make Google Maps even better.
Image via Apple