Thread: China City Navigator NT 2010.21 (CH) for Garmin

Tested on Garmin Mobile XT on HTC Touch HD at home
Seems does not need offset correction file (namely the 6kiB GMAPPROM.IMG file) to find the right location

Originally Posted by lh128

Tested on Garmin Mobile XT on HTC Touch HD at home
Seems does not need offset correction file (namely the 6kiB GMAPPROM.IMG file) to find the right location

Would you please perform following steps before give this try?
1.backup your poi file
2.delete /save folder
3.delete 6kb gmapprom.img and oem img.
4.reboot your PPC/PNA or whatever
5.Change "lock position to road " to "display actual position"
6.restart Garmin

I'm interested with your reviews, because I met some troubles with this. And some other comments on DIY this map suggest some difference.

Originally Posted by lh128

Hey, sorry for the late reply. Kinda busy last week.

I started this time with a new ROM flash (it will delete everything) and cleared my storage card with a card reader. So it's as clean as new.
But of course I installed Chinese language support to display Chinese characters. It only involves copying a font file and modifying some registry key.

First, extract the file downloaded in this forum > GPS Navigation Systems > Navigation Softwares > [Windows CE 6.0] Garmin Mobile XT v5.00.30w ASN
Sorry my account does not have the privilege to post a direct link.
It only includes Mobile XT program, without gmapprom.img or anything.

Then, use the "you know what" to generate an sw.unl file.

Finally, copy the base map and unlocked detailed map provided in the first post, and change settings in Tools - Settings - Map - Show Location, from "on roads" to "at GPS location".

I walked from office to subway station, and subway to home. The position was correct all the way.

Hope it's helpful.

Is that because the map had already been corrected? Or Garmin finally tried of making offset?

Originally Posted by godeyes

Is that because the map had already been corrected? Or Garmin finally tried of making offset?

First, further tested with other base map and ruled out the possibility of that.

Then tested with older version of China map (701 NT17) and I'm way off the point as expected. My location on the old map was about 500m NW. But the position is correct with map 760 and 2010.21.
On other hand, my coordinate was quite different during the test. On newer maps, my coordinate was about 500m SE from the actual one, according to Google Earth.

So the conclusion is: From version 760 on, the former offset correction file, namely the 6kiB GMAPPROM.IMG file, is included in the map and will change the coordinate instead of change position showed on the map. Anyone with a problem displaying those maps should consider upgrading their software to support the integrated file.

And Garmin will certainly continue making offset, as long as it stays in business in China. The government believes the coordinate is "national security" issue and requires all map publishers make offset, thought anyone now can just download Google Earth and have the exact coordinate.

Originally Posted by zerozero1

Hi lh128,

When I use the older map (Map 650) when I visited China last June, I added a file "006B082300.bin" to the /GARMIN directory (i.e., the same directory as the gmapsupp.img). This "006B082300.bin" file corrected the offset (position and coordinate). Have you heard of such a file? Do you know if it work for Map 760 and 2010.21. You can get this file from dropbox if you need it for testing.

Thanks.

As I said before, there is no way you can get both correct position and coordinate at the same time, using an official Chinese map, because of the government regulation.
The so called "offset correction file", ie. 006B082300.bin / GMAPPROM.IMG, is actually a coordinate offset file. By shifting the coordinate to the opposite direction, together with the offset map, Garmin will find the correct location for you. Now this file is part of the big IMG so you can get rid of the file and make things much easier. So basically, you no longer need the file if you use version 760 or 2010.21. But since you already have it, you may also keep it for insurance, because at least for me, keeping the stand-alone correction file with a integrated map won't shift my coordinate twice.

And it seems, at least what I saw on a Taiwan website, that the 006B082300.bin file only works for Nuvi / some Oregon models. So sorry I'm not able to test that for you. If you're using Mobile XT as I am, I can say for sure that you don't have to put the "correction file" into Garmin folder anymore.

Hope it clears your doubt.