A point and a radius calculation -- please help!!!

Hi,

        Hope that you can help me. I have a wee problem that I can't figure
out.

        I have the X-Y co-ordiates of a point in latitude & longitude format
(specified in decimal-degress). I also have the distance in km of the
radius of a circle around this point.
        My question is this: is there a nice formula for calculating the 4
points around this central point using the radial distance? The points
that I'm interested in are the ones directly vertical & horizontal -
do you know what I mean? Forming a kind of a plus sign...

        Any comments/suggestions/pointers much appreciated.

Cheers,
Al.

Hello Al,

basically what you are looking for is "Destination point given distance
and bearing from start point". Calculations for this can be performed at
http://www.movable-type.co.uk/scripts/latlong.html , and this site also
gives the formulas to perform this calculations.

Willem

almurph@altavista.com wrote:


--
Willem van Deursen, The Netherlands
wvandeursen_nospam@nospam_carthago.nl
replace _nospam@nospam_ for @ to get a valid email address
www.carthago.nl

wrote:

Proj.4 has code for great circle distance already programmed to give
your answers.
http://remotesensing.org/proj/