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[nycphp-talk] Deconstructing google maps

inforequest 1j0lkq002 at sneakemail.com
Tue Apr 5 22:58:45 EDT 2005


Rolan Yang rolan-at-omnistep.com |nyphp dev/internal group use| wrote:

> inforequest wrote:
>
>>
>> Rolan I find Google's map to be consitently "off" several hundred 
>> feet or more. I don't understand your comment about conversion error, 
>> but do you also see the display being off?
>>
>> -=john andrews
>> _______________________________________________
>
>
> It doesn't seem off that much to me. Where are you looking? What I 
> meant by conversion error is that when determining Google's scheme for 
> converting the tile coordinates to lat/lon, the 0,0 point came out to 
> 39.50N 98.35W decimal. The actual geograpic center of the Conterminous 
> United States is 39°50'N 98°35'W *  which would actually be 39.83N 
> 98.58W decimal.
>
> * as noted in 
> http://erg.usgs.gov/isb/pubs/booklets/elvadist/elvadist.html
>
> ~Rolan

Thanks for clarifying.

I determined that the positioning error I am seeing is in the street 
address coordinates database. It looks like they are using the Census 
data, because the addresses are off equally in the census 2000 data and 
Google's map.





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