Garmin Mapsource maps download - MapLoader

MapLoader are a plugin for GPSExplorer.

Maploader can:

Download maps to Garmin compatible units. They appear to be functioning ok but the program are built on some guesses so it is possible that they may destroy you unit. YOU USE THE PROGRAM AT YOUR OWN RISK!

MapLoader problem

Doesn't remove routing information from MG-Europe maps when sent to a unit which supports routing. The map gets routable inside the unit.
Can't handle new type of maps perfectly. The search index is not transferred to the unit. (MDR). New products are: MG-USA II, MG-Europe, RR-Europe, City-navigator, City-Select, POI maps. Searching for nearest POI's work, nothing else... The map is shown correct, but the searching doesn't work.
Need to have access to all files when downloading, can't swap cd's.
Possible hangups when the GPS doesn't respond perfect.
Not possible to save selected maps.
Almost no documentation. :-(

Usage

No usage description yet, but guess how it works...

FAQ about map downloading

Q1. Is it possible to do incremental map download?

The memory in the unit is like a filesystem so Garmin can most likely, if they want to, add the possibility of doing incremental downloading by releasing a new mapsource program. It is very unlikely that they have to do any changes in the GPS.

Q2. If it is possible, Why doesn't your program do incremental map download?

I don't know the serial command "Set program area to map-flash". Normally erase flash does that.

Q3. Why so slow download?

All data is sent in packets.
All data-packets are maximum 255 byte length.
Effective data in each packet 250 bytes. (4 bytes adress, 2 byte alignment)
Each datapacket are acknowledged before the next one is sent.

For each 250 byte data :
sending side: 250 + 6 (header) + time to parse ack packet.
receiving side: 8 (ack packet) + time to parse data packet.
=> 264 bytes + 2*parse time. == 2640 bits (1 start and 1 stop)

24 Mbytes = 100 663 data packets. => 265750320 bits sent
With 115 kbit/s. => 2306 s = 39 minutes
39 minutes are absolute minimum of 24 Mbyte download data when no time is taken in parsing the 200 000 packets.

Garmin Serial Emulator - GarminSimulator

Use the plugin GarminSimulator to debug the downloading of maps. Not perfect, but quite ok. To start GPSExplorer with the simulator:
java -cp GPSExplorer_XXX.jar GPSExplorer GarminSimulator

Garmin Mapsource Map Extraction - MapExtractor

This plugin can be used to extract maps from a unit which has maps downloaded with mapsource inside.

The maps are not identical with the ones transferred from the beginning to the unit, but the data in the map is identical.

Known problems

Not all maps can be retrieved from the unit.
If something goes wrong during extraction, it is a huge possibility that both the GPS and the program needs a restart. (The serial speed is changed from default during transfer for faster extraction.)