[Mapserver-users] distance from lat-long

[Jerl Simpson]

Changqing,

Using PHP, this seems to work well for me.  It's not completely precise, 
but it's pretty close for small areas.

$A=abs($Lat1-$Lat2)*111195;
$B=abs($Lon1-$Lon2)*111195*cos(deg2rad(($Lat1+$Lat2)/2));
$C=sqrt($A*$A + $B*$B);  // gives distance in meters between two points


Jerl

Changqing Zhou wrote:

> Hi, I feel I am really asking a stupid question here. So please just
> discard if it makes you laugh.
> 
> I have a pair of lat-long. My assumption is that my area is very small,
> like in a city.
> 
> 1)Is there a simple equation I can use to calculate the distance in
> meters of those two points?
> 
> 2)If I do d = sqrt [ sqr(p1.lat - p2.lat) + sqr(p1.long - p2.long)], does
> d mean anything at all?
> 
> Thanks,
> 
> Changqing
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