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From Chen Li <>
Subject Re: Will it go 'round in circles?
Date Sat, 08 Aug 2015 05:41:15 GMT
I second Ted's argument.  The reason on,148162,152625#msg-152625 is very
weak, since following that logic there will be no 100% lines or
rectangles on the surface of the earth.  But these shapes are very

I am sure there are use cases for circles, such as the Apple's new
headquarters.  A related question is: what's the overhead of
implementing and maintaining this type?


On Fri, Aug 7, 2015 at 2:04 PM, Ted Dunning <> wrote:
> There you go.
> Another application.
> On Fri, Aug 7, 2015 at 1:43 PM, Mike Carey <> wrote:
>> AND:  What if NASA wants to use us to store its database of crop circles?
>> :-)
>> On 8/7/15 11:47 AM, Ted Dunning wrote:
>>> On Fri, Aug 7, 2015 at 3:23 AM, Chris Hillery <>
>>> wrote:
>>> I've noticed that several geospatial serialization formats (at least
>>>> "well-known text" and GeoJSON) omit "circle" from their list of basic
>>>> geometric forms, even when they have numerous more complex types such as
>>>> multi-curves. This led me to here:
>>>> which offers a reasonably compelling argument for why "circle" is not a
>>>> reasonable shape to discuss in geospatial contexts (loosely, because
>>>> there's no consistent way to map that to a spherical coordinate system).
>>>> Actually, that argument is super-weak.  It also implies that you
>>> shouldn't
>>> have lines (they aren't straight after projection) or squares (they aren't
>>> square after projection). But lines and squares both before and after
>>> projection are very handy.
>>> Circles are useful in many contexts. Drawing the visible horizon for a
>>> particular observer is a great example.  The flight range of an airplane
>>> is
>>> another case.  Positional error bounds with Gaussian errors is another.
>>> Yes. You can approximate it using splines or polygons.  But you can
>>> approximate anything that way.

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