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margust

china map for garmin

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helloo

 

has anyone information, where to get chinese map for garmin? garmin doesnt seem to have one but perhaps there are alternatives? chinese garmin agents are quiet and wont ansver to english speaking emails :laughing:

or would it be smart to find one from there?

 

m

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I seem to remember seeing something recently about how using a GPS in China would be considered as spying so that could be why they are not answering a foreigner, maybe.

Edited by goedips

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I seem to remember seeing something recently about how using a GPS in China would be considered as spying so that could be why they are not answering a foreigner, maybe.

 

I don't believe that is an issue. During the last four years I have used a GPS openly in China as a foreigner without incident.

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helloo

 

has anyone information, where to get chinese map for garmin? garmin doesnt seem to have one but perhaps there are alternatives? chinese garmin agents are quiet and wont ansver to english speaking emails :)

or would it be smart to find one from there?

 

m

MapSource World Map covers China - but only at basemap level accuracy, of course. Might tide you over until you get to China and see what you can pick up locally.

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This is what I am able to find. Hope it's useful to other people that are looking for the same information.

 

Garmin has teamed up with a local company, http://www.unistrong.com/, to produce the China maps. When you guy a Garmin GPS in China, you get a unit with a modified/localized firmware by UniStrong. The unit also comes with a pre-installed map of China on the SD card, in the form of a gmapsupp.img file. You don't get the DVD or the mapsource version of the map. The map is locked and only works with the specific unit.

 

With some work, you can find City Navigator China online, both in English and Chinese. These are not the mapsource DVD version, but rather the gmapsupp.img file that people have shared. Using tools such as GPSDaemon or gmaptool, you can split this file into its components, and using additional tools, you can hack up some additional files and make the map visible in mapsource, all works beautifully when you do it correctly.

 

Now before you get too excited, the real deal breaker is in the map itself. The government, in their infinite stupidity and paranoia, has applied a positional shifting algorithm to the map data before giving it out to the various map vendors. The shift is not constant, probably linear, and is in the order of couple of hundred meters. Not much but enough to make precision navigation using the GPS all but impossible. I verified this with waypoints I've marked in China. In Shanghai, they are off by probably 600 meters. In southern china, Nainan, it's off by something like 300 meters. Some have claimed that the shift is the same for a lot of the digital maps in China, and someone has compiled a correction table based on latitude and latitude, but are afraid to publish it.

 

So how do the GPS sold in China overcome this problem? The answer is in the customized firmware. The Garmin firmware used in China (again not available as a general download), can read a gmapoem.img file, and applies correction to the map data based on information encoded in the file.

 

So what does all this mean? It means that even if you go through the trouble of finding the map, you probably can't use it in your English 60csx unit. The map is probably only useful for viewing in Mapsource, unless you can find the localized Garmin firmware (extremely hard). Of course you can always just buy one in China, but it just seems silly.

 

I hope one day their government will change the rules to allow digital maps of China to be sold over seas, then you will be able to buy the map from Garmin, and use it in China. It will probably happen when GPS becomes a commodity in China and no one cares about it anymore. :laughing: In the mean time, you'll have to rely on the public domain maps.

 

For more info, see http://www.pda4x.com/thread.php?fid=16

Edited by wildgoose007

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