Nokia N95 and GPS Maploader – backup of countries

To download complete maps for the GPS navigation in the N95, the first choice is Nokia’s Maploader, easily downloaded and installed. With maps of almost all countries available, you’ll probably get very short on space on your micro-SD card. One way around this is downloading and backing up countries you will not need every day.

File storage directory for GPS maps

But managing the maps for GPS and backing up maps of single countries is not done by point and click.. The GPS maps are stored in single squares covering the area of 50 to 1,000 sqkm (depending on the street-density etc.) with hex-filenames, that don’t make sense to me yet. What I do know is, that there’s no folder like “Germany” or “England” you can simply backup on your harddrive. The Maploader stores the files in a directory-tree with names “0″ to “9″ and “a” to “f”, the signs available in hex. In each of these directories there are similar directories named “0″ to “f”, therefore you have 256 directories in the folder X:\Private\20001f63\diskcache\ on your micro-SD card that hold the data for all countries that you download. Each country provides uniquely named square-files except for areas at the border between two countries that are included in both country’s maps.

Howto backup countries from maploader

So the clue for downloading and storing your maps in an easily accessible backup is downloading and backing up only one country at a time; just do this:

1. Delete all directories in “X:\Private\20001f63\diskcache\” except the 4 files in the directory.

2. Download a country with maploader.

3. Backup the directory “X:\Private\20001f63\diskcache\” to a directory, that you name with the country you just downloaded.

4. Start over with step 1.

I didn’t get any difference between the files in die diskcache yet, Cachedatheader.cdt, config.cfg, ffffffff.cdt and qt. You can back them up or just use the ones you have already. They obviously just store the last file you downloaded etc.

Format your micro-SD with FAT32 to save storage space

There’s one more important point: The map files are pretty small, some of them are less then one kb; so with 10 MB downloaded files you’ll probably fill 25Megs of your micro-SD card, because by default it’s formated with FAT16 and each of the 1kb-files fills 16kb on your card; so back your card up and format it in FAT32 in your cardreader you hopefully have. That saves you at least 50% of the space used by the maps on your card. Though I read, that micro-SD and S60 cannot handle FAT32, I tried it and it works.

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