Hi Frank,
The distance measurements have nothing to do with the projection.
They are based, rightfully so, on elipsoid (Geo) and spherical
(GreatCircle) models. As you move north, distances between
longitudes get smaller (look at a globe with graticule lines and
measure the physical distance on the globe between longitude lines).
Hope this helps,
Don
On May 31, 2007, at 9:55 AM, F.Bayliss wrote:
> All,
>
> I'm confused. I'm using the Mercator projection and displaying the
> US in my application. I wanted to know the distance (miles and
> kilometers) between two points. I've tried using Geo.distanceNM &
> KM and I even copied some code from DistanceMouseMode using
> GreatCircle.spherical_distance. What I've found is the distance
> between two identical length longitudinal lines at different
> latitudes have different length. Why? Isn't the map displayed flat
> so the width, lets say - Wyoming being close to square, is the same
> width at the top and bottom borders? Help.
>
> Thanks
> Frank
>
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Don Dietrick, dietrick_at_bbn.com
BBN Technologies, Cambridge, MA
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Received on Fri Jun 01 2007 - 10:24:01 EDT