angsepd
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Contents: Description, Arguments, Usage, Examples, Sub-Functions, Related Functions, Source Supported Under Version: > 1.22
Description Computes the angular separation (great circle distance) between two pairs of coordinates.
Arguments and Return Values Parameters: Four inputs specifying the latitude and longitude of the points in question, in degrees. Return Value: A value specifying the angular separation between the two points, in degrees.
Usage Syntax: angsepd(lat1, lon1, lat2, lon2) 'lat' and 'lon' are numeric This function is only exact (within machine precision) for points on a sphere. Planets are not perfect spheres, but treating a planet as a sphere is a sufficiently accurate approximation for most purposes. This function should work when given array inputs, but this has not been extensively tested. Return format is double if input is double; float otherwise This function simply applies the formula θ = acos(cos(lat1)*cos(lat2)*cos(lon1 - lon2) + sin(lat1)*sin(lat2)) from http://mathworld.wolfram.com/GreatCircle.html When angsepd() is entered without any arguments, it prints its description, as shown below.
Examples dv> angsepd() Given two pairs of coordinates, returns angular separation angsepd(lat1, lon1, lat2, lon2) All inputs should be in degrees. Output is in degrees. This is the great circle distance (for a sphere). See http://mathworld.wolfram.com/GreatCircle.html S.Marshall 10-27-2009 0 dv> angsepd(0, 0, 45, 180) 135.000000000000 dv> angsepd(0, 0, 45, 45) 60.0000038146973 dv> angsepd(double(0), double(0), double(45), double(45)) 60.0000000000000 |
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Recent Library Changes Created On: 11-17-2009 |
