Hacker News Reader

Comment by bigwally | Hacker News Reader

This is not a problem with using a GPS, the problem is the shift from using different mapping technologies.

Trying to get satellite and the map portions to line up is very difficult. Trying to do it on a global scale with data from multiple sources... you get the idea.

Now please get back to China bashing and don't let the facts get in the way of your political/religious feelings. Remember to include lots anecdotal evidence and use the word red. And as always bring up other countries that seem scary on fox news.

View on HN

>Now please get back to China bashing and don't let the facts get in the way of your political/religious feelings. Remember to include lots anecdotal evidence and use the word red. And as always bring up other countries that seem scary on fox news.

I don't know if the author's analysis is accurate, but I'm pretty sure the author is Chinese. I doubt he is repeating what he hears on Fox News.

Trying to get satellite and the map portions to line up is very difficult. Trying to do it on a global scale with data from multiple sources... you get the idea.

Not really. There are loads of different projection systems & coordinate system around the world, so all GIS software is able to deal with converting coordinates and reprojections etc.

Satellite & aerial imagery always has to be georectified and made 'location aware'. Once you've done that, it's trivial to reproject it to whatever system you want.

While I understand your cynicism, my experience in Shanghai and Beijing suggests that Google Maps are some way off between satellite and streetmap modes. I have not found the same problem (or at least to anywhere near the same level) in the UK, Chicago, Michigan, Korea, Japan, Germany, Slovakia and many other countries. There does seem to be an offset applied.

An example in Shanghai: http://g.co/maps/m34n8 An example in Seoul: http://g.co/maps/4gk3t

Note the near perfect alignment in the latter, and way-off alignment in the former.

No where else has more sky scrapers than Shanghai and Beijing, which easily affects your GPS signal.

If you mean buildings over 100m, then no:

    1 	Hong Kong
    2 	New York City
    3 	Tokyo
    4 	Dubai
    5 	Shanghai

Beijing is #20.

http://en.wikipedia.org/wiki/List_of_cities_with_most_skyscr...

I suspect that Tokyo might well have more. Anyway, the loss of accuracy in such a case wouldn't cause a consistent effect like this - it's normally not in a consistent direction and generally doesn't put you off by so far.

While I agree - in different words - that it's probably just a projection error, it is always extremely off-putting when the Overbearing Defensive Cyber-Army makes its appearance to defend China from any and every possible criticism.

It really does much more harm to China than a simple misunderstanding about projection errors.

Reply on news.ycombinator.com