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Do Not order City Navigator China v2008

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I have seen people reported offset error in map of China used on GPS not bought in China.

 

Now this has been confirmed by other on the new v2008.

This will not be fixed by Garmin.

 

Do not order this map, unless you do not have a GPS bough in China.

 

http://www.gpscity.com/msdcnchina

 

Michael writes:

Rating: 1 of 5 Date: 2008-08-04

I am in China now with this map. I bought the City Navigator to use with my Nuvi 660. There is a fundamental problem with the maps. Your position has a constant offset that puts you about 400 meters from your acutal position making it impossible to use. Routing is not possible because it will continually recalculate because it thinks you are off the road you are on. This is probably due to a map datum offset. Probably an easy fix for Garmin. Hope they come out with an online fix so I can use it here.

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A GPS bought with this map in China do have a special firmware patch to remove the 400m offset.

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I imagine this has nothing to do with using non-Chinese units with Chinese maps. It's most likely the other way around. This is to prevent gray-market Chinese units from flooding other markets. What you've experienced is just an unfortunate side-effect.

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But - if You are in China with "normal" GPSr and You have bought this map, it is good to make two dots on screen for two chosen ( more frequently used) zoom values ( for shift 400mtr - zoom say 800mtr and 1,2km).

Just stop in known position and mark theese dots on screen at this point of map.

Dots present Your real position. Dont use another zoom for positioning.

Primitive but simple and practical when the map has a shift and You have no time and idea about datums, projections ...

 

Christopher

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WOW! I'd be inconsolably PISSED if I bought that crap and traveled all the way to China! How could Garmin release those maps with such a fundamental error? ;)

 

Boo! Hiss! ! Moony-1.gif

Edited by Neo_Geo

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This is not the first version of maps with this offset.

Same reported for other GPS maps

 

I think the map has random error mandated by the Chinese Govt. Unless you buy the GPS unit in China with a local firmware, all oversea unit will have this random positional error (up to 500 m).

 

Jeff

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Check out www.openstreetmap.org for accurate (if incomplete) maps of China. Accurate because they were surveyed with non-broken GPS equipment. OpenStreetMap was good enough (better than Google) for Flickr to change over to show their map data instead for China. OSM maps can be put onto a Garmin GPS (non-routing) using a tool called mkgmap.

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Here is what I did got from Garmin while I asked them about this:

 

First Mail

Question:

Is there an offset problem using China maps on any GPS

 

Answer:

Thank you for contacting Garmin International.

 

I will be happy to assist you, this may be that the unit software needs

to be update to up grade the satellite software to correct the issue of

the location on the mapping, this can be done on the Internet please

click on the link to update unit firmware:

http://www8.garmin.com/support/collection....ct=999-99999-27

 

Next Email

Question:

Can you answer the question.

If buy China City Navigator v2008 and put it on my Europan Nüvi 760,

will it be spot on all road, and routing will work?

 

Give me one answer. YES or NO

 

People has reported that you need a GPS bought in China to not

get an offset anser.

 

Answer:

Thank you for contacting Garmin International.

 

Yes

 

So there may not be any problem at all ??

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Here is what I did got from Garmin while I asked them about this:

 

Next Email

Question:

Can you answer the question.

If buy China City Navigator v2008 and put it on my Europan Nüvi 760,

will it be spot on all road, and routing will work?

 

Give me one answer. YES or NO

 

People has reported that you need a GPS bought in China to not

get an offset anser.

 

Answer:

Thank you for contacting Garmin International.

 

Yes

 

So there may not be any problem at all ??

I think that hinges on whether or not your in agreement of what Garmin perceives as being a "problem".

No one can seem to get Garmin to truly acknowledge the 'positional wandering' issue that the Colorado

and HCX users seem to arbitrarily experience during and after low signal strength situations.

This new aspect of Garmin's customer service/relations policies could be troubling to those shopping

for new handhelds, I know I find it such. Seems to be reminiscent of the waning days of Magellan's

handheld adventures.

 

Norm

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I can confirm this as being an issue. I have a friend who is over there who took his Colorado with him with the China SD card and there is a 400 ft offset. No question about it. However he purchased anothergarmin gps over there in China and put the SD card and it is working fine now. He plans on ebaying the chinese unit when he gets back to get his money back since he won't be going to China again any time soon.

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So far any solution available using not China made GPS ???

G.

www.openstreetmap.org Coverage is not great, but you can help improve it!

 

I have an upcoming trip to China and I just created a map for my Vista HCx. It wasn't trivial and the results are not spectacular, but it seems to work. You might have better luck downloading the pre-compiled version from Cloudmade here. Grab the china.img.zip file, then just drop that gmapsupp.img file on your memory card under the Garmin folder and you'll be all set. Note that with that solution, you won't be able to have any other maps on your GPS at the same time (unless you have a Colorado or Oregon and you do tricks with the internal files). That was the reason I created my own.

 

I've heard there may be a way to combine maps using GMapTool, but I haven't tried it myself.

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So far any solution available using not China made GPS ???

G.

www.openstreetmap.org Coverage is not great, but you can help improve it!

 

I have an upcoming trip to China and I just created a map for my Vista HCx. It wasn't trivial and the results are not spectacular, but it seems to work. You might have better luck downloading the pre-compiled version from Cloudmade here. Grab the china.img.zip file, then just drop that gmapsupp.img file on your memory card under the Garmin folder and you'll be all set. Note that with that solution, you won't be able to have any other maps on your GPS at the same time (unless you have a Colorado or Oregon and you do tricks with the internal files). That was the reason I created my own.

 

I've heard there may be a way to combine maps using GMapTool, but I haven't tried it myself.

Thank you, but I paied stupidly so much money for that useless map so I want to be more stupid awaiting someone ( Grarmin??) who can solve the problem. ;)

G.

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Foreign countries use many of the multitudes of map Datums that all GPS's have but that we all ignore except for WGS84 and NAD27, perhaps Garmin is not a USA company and keyed their China maps to a China Datum? Changing your Datum should remove any offset of any kind, if it's what i'm suspecting.

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Foreign countries use many of the multitudes of map Datums that all GPS's have but that we all ignore except for WGS84 and NAD27, perhaps Garmin is not a USA company and keyed their China maps to a China Datum? Changing your Datum should remove any offset of any kind, if it's what i'm suspecting.

 

No.

 

The maps have a purposeful inbuilt error that can only be fixed by using a GPS purchased in China. Those units have a special firmware that corrects the error. It is a well known and long standing issue.

 

The big point here was that they started selling the maps outside of China and did not correct the problem.

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Foreign countries use many of the multitudes of map Datums that all GPS's have but that we all ignore except for WGS84 and NAD27, perhaps Garmin is not a USA company and keyed their China maps to a China Datum? Changing your Datum should remove any offset of any kind, if it's what i'm suspecting.

No, it's because the Chinese government is paranoid. They coerced Garmin (and other manufacturers) to put in certain offsets (which are not constant) into the map data, which are then corrected by a special firmware installed in Chinese market GPS receivers.

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Here is what I did got from Garmin while I asked them about this:

 

Next Email

Question:

Can you answer the question.

If buy China City Navigator v2008 and put it on my Europan Nüvi 760,

will it be spot on all road, and routing will work?

 

Give me one answer. YES or NO

 

People has reported that you need a GPS bought in China to not

get an offset anser.

 

Answer:

Thank you for contacting Garmin International.

 

Yes

 

So there may not be any problem at all ??

I think that hinges on whether or not your in agreement of what Garmin perceives as being a "problem".

No one can seem to get Garmin to truly acknowledge the 'positional wandering' issue that the Colorado

and HCX users seem to arbitrarily experience during and after low signal strength situations.

This new aspect of Garmin's customer service/relations policies could be troubling to those shopping

for new handhelds, I know I find it such. Seems to be reminiscent of the waning days of Magellan's

handheld adventures.

 

Norm

 

I have definitely experienced the offset issue with low signal strength situations as well as low battery situations. Quite annoying.

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What you probably need to do is use a user-defined custom datum to get the maps to line up.

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What you probably need to do is use a user-defined custom datum to get the maps to line up.

 

Datums do not affect the maps......

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First of all I apologize for my poor English.

Some week ago I informed by mail the Garmin Italian sales dept about that problem; they was very kind and courious about that, asking for the more information I got. So I sent many snapshot and some waipoint, where they appear on the map, and simultaneously the location where they should appear. But after that they keep silent, no more answer or explanation. I sent many mails...but no answer. Than I contact the English Garmin Map dpt. The only suggestion I received was: ask your supplier to refund your money....

G.

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When I email Garmin tech support I do get a replay that I need to use latest firmware. They do not confirm or deny that there is any problem.

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Next answer from Garmin regarding if there is an offset on Garmin GPS in China.

 

Do my Colorado and Nüvi work in China without offset error?

 

Answer Garmin

Yes, both the Nuvi and Colorado will work anywhere in the world, as long

as they have a view of the sky. It may take longer than usual to

acquire satellite signal in the new location the first time. The next

time the unit is used, it will be much quicker.

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Next reply.

 

Why should Garmin lie?

 

The unit will be just as accurate in China as it is the US (accurate to

about 9 feet at best). The problem discussed in the forum could be the

result of a number of errors. The user could be using a different

position format or map datum, which would result in inaccuracies.

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Do my Colorado and Nüvi work in China without offset error?

Yes. I read from these posts that it's a fudging of the China maps, not a smudging of the GPS's reported position.

 

We can turn off, or is it on, selective availability on a regional basis, but I don't think that we (the USA owners of the GPS satellite segment) would blanket the whole country of China for their benefit. After all, if we want to send a nuke there we want it to go where we want it to go.

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Do my Colorado and Nüvi work in China without offset error?

Yes. I read from these posts that it's a fudging of the China maps, not a smudging of the GPS's reported position.

 

We can turn off, or is it on, selective availability on a regional basis, but I don't think that we (the USA owners of the GPS satellite segment) would blanket the whole country of China for their benefit. After all, if we want to send a nuke there we want it to go where we want it to go.

 

I used a PPC Loox N560 with Tomtom 6 and BeeLine GPS last year, no problem at all....

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Just to make sure not to confuse, the GPS will show correct position.

Problem is the map for China that will show an offset error if you do not have a GPS bough in China with a spesial firmware that do correct this error (on Garmin GPS)

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And the final reply from Garmin

 

The City Navigator China map will be accurate. The only difference in

the units that we sell in China and those that we sell in the US is the

languages that they display, and the artwork on the box they are shipped

in. A unit bought in China will perform the same as a unit bought in

the US with the City Navigator China map loaded to it.

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What you probably need to do is use a user-defined custom datum to get the maps to line up.

 

Datums do not affect the maps......

That's right, they don't. But they can possibly align the maps' position properly.

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And the final reply from Garmin

 

The City Navigator China map will be accurate. The only difference in

the units that we sell in China and those that we sell in the US is the

languages that they display, and the artwork on the box they are shipped

in. A unit bought in China will perform the same as a unit bought in

the US with the City Navigator China map loaded to it.

So I would somebody explain to me why my Colorado show 500 mt offset with City Navigator China and work properly with South Asia map ( Hong Kong etc.) :)

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Send an email like I did to Garmin and see what they do reply.

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Datums do not affect the maps......

 

Paper maps no, but how your GPSr translates the coordinates does. Here is the definition for datum form the ArcGIS website http://webhelp.esri.com/arcgisdesktop/9.2/...opicName=Datums

 

While a spheroid approximates the shape of the earth, a datum defines the position of the spheroid relative to the center of the earth. A datum provides a frame of reference for measuring locations on the surface of the earth. It defines the origin and orientation of latitude and longitude lines.

Learn more about spheroids and spheres

Whenever you change the datum, or more correctly, the geographic coordinate system, the coordinate values of your data will change. Here are the coordinates in DMS of a control point in Redlands, California, on the North American Datum of 1983 (NAD 1983 or NAD83).

 

-117 12 57.75961

34 01 43.77884

 

Here's the same point on the North American Datum of 1927 (NAD 1927 or NAD27).

 

-117 12 54.61539

34 01 43.72995

 

The longitude value differs by approximately three seconds, while the latitude value differs by about 0.05 seconds.

 

NAD 1983 and the World Geodetic System of 1984 (WGS 1984) are identical for most applications. Here are the coordinates for the same control point based upon WGS 1984.

 

-117 12 57.75961

34 01 43.778837

 

Geocentric datums

In the last 15 years, satellite data has provided geodesists with new measurements to define the best earth-fitting spheroid, which relates coordinates to the earth's center of mass. An earth-centered, or geocentric, datum uses the earth's center of mass as the origin. The most recently developed and widely used datum is WGS 1984. It serves as the framework for locational measurement worldwide.

 

Local datums

A local datum aligns its spheroid to closely fit the earth's surface in a particular area. A point on the surface of the spheroid is matched to a particular position on the surface of the earth. This point is known as the origin point of the datum. The coordinates of the origin point are fixed, and all other points are calculated from it.

 

localvsearthdatum2.gif

 

The coordinate system origin of a local datum is not at the center of the earth. The center of the spheroid of a local datum is offset from the earth's center. NAD 1927 and the European Datum of 1950 (ED 1950) are local datums. NAD 1927 is designed to fit North America reasonably well, while ED 1950 was created for use in Europe. Because a local datum aligns its spheroid so closely to a particular area on the earth's surface, it's not suitable for use outside the area for which it was designed.

 

I do suspect it is that the incorrect datum has been selected. When you make maps and import other feature layers if the datum isn't correct or is projected to the new coordinates then you will see a shift in X & Y coordinates.

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When I was in China I try to change almost all datum available on my Colorado, but no difference on shift.

I sent many mails to Garmin, but Italian garmin no answer anymore to further mails, and Garmin England suggest to ask money back to the supplier. ( I bought maps in HKG, but now I am in Italy)

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