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Re: CRS best practices: Google Geocoding API

From: Ed Parsons <eparsons@google.com>
Date: Fri, 03 Mar 2017 16:02:15 +0000
Message-ID: <CAHrFjcnv08tfRMvLM_o8wsueTyiQtES0ty8Lf0-7S6GVhvO9nw@mail.gmail.com>
To: Jeremy Tandy <jeremy.tandy@gmail.com>, SDW WG Public List <public-sdw-wg@w3.org>
I think you are experiencing the rest of the world view "that I just need
to use Lat & Long - Period :-)"

The use of WGS84 is documented here
https://developers.google.com/maps/documentation/javascript/maptypes if you
go looking for it, must I would argue that most mainstream web developers
don't need to know..

btw this is also quite a nice explanation of tile based spatial indices ;-)

Ed



On Fri, 3 Mar 2017 at 15:14 Jeremy Tandy <jeremy.tandy@gmail.com> wrote:

> Hi Ed- in the introductory material you wrote about CRS you make a
> reference to the Google Geocoding API [1], in that its responses explicitly
> state Lat and Long rather than a coordinate pair of ambiguous order.
>
> Lat and Long are, by definition, angular measurements. OK - got that.
>
> But parsing through the API documentation, I can't see any reference to
> the units or datum which is used.
>
> Being a human, I'm prepared to guess that these are decimal degrees
> (because they look like floating point numbers). Easy for machines to
> figure that out too.
>
> As a human, I'm also prepared to guess that the API uses the WGS84. But
> that is a tricky leap for machines to work out.
>
> Does the API documentation say "WGS84" anywhere? If so, can you point me
> to it so I can refer to this explicitly? And if not, can you either justify
> why it doesn't matter, or get your colleagues to update the documentation
> (and then send me a link!).
>
> (I think that we've all agreed that it's dangerous to _assume_ a CRS :-) )
>
> Thanks, Jeremy
>
> [1]: https://developers.google.com/maps/documentation/geocoding/intro
>
-- 

*Ed Parsons *FRGS
Geospatial Technologist, Google

Google Voice +44 (0)20 7881 4501
www.edparsons.com @edparsons
Received on Friday, 3 March 2017 16:03:01 UTC

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