Re: decimal longitude and latitude problem

very detail answer... thanks a lot.

Dave Seaman wrote:
On 16 Nov 2006 05:32:38 -0800, steve wrote:
Please help...I need to know the formula for calculating a particular
distance from a specific decimal longitude and latitude. For exampl,
for a house located at -77.209528 ,38.716728, what is the latitude and
longitude range for all houses withing .25 miles or .5 miles

It's a problem in spherical trigonometry. Set up a spherical triangle
having two of its vertices at the specified points. The third vertex
should be either the north pole or the south pole, whichever seems
convenient. Then apply the law of cosines for sphereical triangles:

cos c = cos a cos b + sin a sin b cos C

where

c is the distance between the two points,
a is the polar distance (co-latitude) of the first point,
b is the polar distance of the second point,
C is the difference of the longitudes.

If you solve for c in decimal degrees, then multiply by 60 to convert to
nautical miles. In other words, one minute of arc = one nautical mile =
1.15 statute miles, approximately.

For the second part of your question, you need to know that one degree of
latitude is 60 nautical miles, while one degree of longitude is 60*sin L
nautical miles, where L is the latitude.



--
Dave Seaman
U.S. Court of Appeals to review three issues
concerning case of Mumia Abu-Jamal.
<http://www.mumia2000.org/>

.

Relevant Pages

  • Re: Calculating a Distance on the Surface of the Earth
    ... latitude and longitude. ... I'd actually be above the surface of the earth due to the ... to the surface of the earth, I'd like to know the distance between ... longitude of the second point. ...
    (sci.geo.satellite-nav)
  • Re: Could PIC handle this?
    ... Doesn't that mean comparing the distance ... magnitude of the distance, not the actual distance. ... differences between the longitude and latitude of each pair of points you ...
    (comp.arch.embedded)
  • Re: decimal longitude and latitude problem
    ... distance from a specific decimal longitude and latitude. ... latitude is 60 nautical miles, while one degree of longitude is 60*sin L ...
    (sci.math)
  • Re: Questions (Space)
    ... The longitude and latitude I'd say are ... vector quantities; ... defines a distance in a particular direction. ...
    (rec.arts.sf.composition)
  • Re: Haversine Calculator
    ... Well I found a nice little on-line Haversine (the function to compute the Great Circle distance between two points) calculator. ... format, and returns nautical miles: ... Latitude: 33.9459N Longitude: 77.1566W ...
    (rec.boats.cruising)
Loading