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Chi maps out of alignment in Google


Article by: Darren Griffin
Date: 20 Aug 2015

pocketgpsworld.com
A number of sites and blogs have flagged an alignment issue in Google maps of China recently. Presumably sparked by searches to locate Tianjin, the location of the huge explosions last week.

If you view a map of China and overlay it on Google Earth you can quickly see that all the roads and streets are offset from their actual locations. It's even more obvious when you compare a Google Earth view over the border with Hong Kong where the alignments is correct on the Hong King side (as per the headline image above).

So why is this happening? The simple answer is - China. China requires that any mapping of its country observe the GCJ-02 coordinate system rather than WGS-84 used in the rest of the world. This uses an algorithm that offsets the map by random amounts. Google adheres to this requirement as it has a Chinese presence.

Why China insists on this is presumably down to security concerns. China has strict regulations regarding the creation of maps that are used in the country with severe punishments for anyone who flouts them.

Source: Google.com/maps



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Comments
Posted by Kremmen on Thu Aug 20, 2015 1:05 pm Reply with quote

Google driverless cars are going to be fun in China then as they make use of fairly accurate GPS locations Smile


Satnav:
Garmin DS61 LMT-D (In the car)
Garmin 2599 LMT-D (Indoor test rig)
DashCam:
Viofo A119 V3

 
Posted by dales on Fri Aug 21, 2015 4:50 pm Reply with quote

If using a Chinese map, you must use a satnav sold by Garmin China to match the offset.

If using a non-Chinese satnav, it's sometimes possible to get a venus-shifted map to match it.

Dales.


nuvi 2599LMT-D, oregon 700, basecamp, memory-map.

 
Posted by MaFt on Mon Aug 24, 2015 11:33 am Reply with quote

Kremmen Wrote:
Google driverless cars are going to be fun in China then as they make use of fairly accurate GPS locations Smile


I would hazard a guess that any Chinese driverless car would be set to use China's own Beidou positioning system as well as government 'approved' maps.

MaFt


 
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