# RE: [OpenMap Users] How to calculate a lat lon point from a distance

From: Potter, Mark A (UK Rochester) <"Potter,>
Date: Tue, 22 Feb 2005 13:41:03 +0000

Laura,

I think this is what you need - LatLonPoint.getPoint(..):

LatLonPoint getPoint(float dist, float az)
Find a LatLonPoint a distance and direction away from this point, based on the sphercal earth model.

az - radians of azimuth (direction) east of north (-PI <= Az < PI)

You'll have to apply the conversion routines you have mentioned though (although with a bit of imagination for Azimuth I believe N = 0; S=PI or -PI, E=PI/2, W=-PI/2).

I hope this helps.

Mark.

-----Original Message-----
From: owner-openmap-users_at_bbn.com [mailto:owner-openmap-users_at_bbn.com]On
Behalf Of Laura Paterson
Sent: 22 February 2005 12:11
To: openmap-users_at_bbn.com
Subject: [OpenMap Users] How to calculate a lat lon point from a
distance

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Hi,

I am trying to work out how to convert between distances to lat lons.

The user selects a point on the map, and I want to find out the lat/lon that
is a certain distance North,
South, East or West of that point.

The distance may be specified in feet/ metres or miles, although I could do
these conversions programmatically...

I have had a look through the API, and the only way I can see to achive this
is to use the Geo class to do kmToAngle(double km), then
Geo.degrees(<result>) However, I'm not sure if this actually does what I
need or not...

Any suggestions would be great!

Laura
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