AARoads Forum

Regional Boards => International Highways => Topic started by: Buffaboy on September 26, 2015, 07:38:04 PM

Title: Google Maps in China seem off
Post by: Buffaboy on September 26, 2015, 07:38:04 PM
For the first time in a long time, I took Google Maps into China, and I noticed that the imagery did not match up with the roads, for example: https://www.google.com/maps/@39.5936074,116.772858,1347m/data=!3m1!1e3. Why is this?

Edit: And contrary to what it may seem, a site called Tecent has street view available for most of China. Just browsing around the highway systems don't seem much different from those in the U.S. They drive on the right, there's toll roads...
Title: Re: Google Maps in China seem off
Post by: vdeane on September 26, 2015, 11:49:12 PM
It also appears that Google tends to delete roads on the Chinese borders, in particular the border between mainland China and Hong Kong.  The North Korean border, however, sees a zillion roads added.
Title: Re: Google Maps in China seem off
Post by: SignGeek101 on September 27, 2015, 12:12:05 AM
Could be the satellite view be somehow off? I don't know what to believe anymore  :no:
Title: Re: Google Maps in China seem off
Post by: jakeroot on September 27, 2015, 12:19:17 AM
It's been slightly off for a long time (for at least a few years). I'm sure there's a political explanation for it.
Title: Re: Google Maps in China seem off
Post by: Chris on September 27, 2015, 04:11:22 AM
It is due to a different geodetic system. Google uses WGS 84, while China uses GCJ-02. Overlaying them results in an offset.

https://en.wikipedia.org/wiki/Restrictions_on_geographic_data_in_China#GCJ-02
Title: Re: Google Maps in China seem off
Post by: webfil on September 27, 2015, 10:16:45 PM
Well the choice of a geoid model over another is quite a good political explanation, as technocratic as it gets.
Title: Re: Google Maps in China seem off
Post by: vdeane on September 28, 2015, 01:21:30 PM
Still curious what's going on with all the extra roads here: https://www.google.com/maps/@40.1065832,124.3850145,15z

Here's another oddity.  Looks like Google just started deleting things when they crossed over into Hong Kong.
https://www.google.com/maps/@22.5141966,114.075532,15z
Title: Re: Google Maps in China seem off
Post by: english si on September 28, 2015, 01:42:49 PM
Quote from: vdeane on September 28, 2015, 01:21:30 PMHere's another oddity.  Looks like Google just started deleting things when they crossed over into Hong Kong.
https://www.google.com/maps/@22.5141966,114.075532,15z
That's applying standard projection to Hong Kong, and where stuff falls over the border from China, but boy it looks odd.
Title: Re: Google Maps in China seem off
Post by: CNGL-Leudimin on September 28, 2015, 04:07:18 PM
China and their things. If the government doesn't like anything, they block it. This has happened with Twitter, and in response I've set up a counter-block, I refer to China as an 'unknown land'. However, I was able to bring Shanghai back to known lands due to its metro serving as the base for a fictional one, and now I refer to as Dairon. But only in Twitter. Elsewhere, I still refer to them as China and Shanghai, respectively.
Title: Re: Google Maps in China seem off
Post by: Buffaboy on September 28, 2015, 06:03:54 PM
Interesting discussion.