Are navigation CD-DVD's from one manufacturer able to be read by navigation units made by another? I have a Harman-Kardon in dash navigation unit and not particularly thrilled with the info provided by the DVD. I'm wondering if I tried a DVD made by another source I might be more pleased with the results.

 

No harm in trying, but I highly doubt your going to get useful results. Companies pay big bucks for that data, so they usually massage it in some proprietary way and compress it.