## Copyright (C) 2020 The Octave Project Developers ## ## This program is free software; you can redistribute it and/or modify it ## under the terms of the GNU General Public License as published by ## the Free Software Foundation; either version 3 of the License, or ## (at your option) any later version. ## ## This program is distributed in the hope that it will be useful, ## but WITHOUT ANY WARRANTY; without even the implied warranty of ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ## GNU General Public License for more details. ## ## You should have received a copy of the GNU General Public License ## along with this program. If not, see . ## -*- texinfo -*- ## @deftypefn {} {@var{lat}, @var{lon} =} gcxsc (@var{lat1}, @var{lon1}, @var{az}, @var{lat2}, @var{lon2}, @var{r1}) ## @deftypefnx {} {@var{lat}, @var{lon} =} gcxsc (@var{lat1}, @var{lon1}, @var{az}, @var{lat2}, @var{lon2}, @var{r1}, @var{angleUnit}) ## Determines the intersection points between a great circle and a small circle. ## ## Input: ## @itemize ## @item ## @var{lat1}, @var{lon1}, @var{az}: latitude, longitude, and azimuth of the ## great circle. These must be scalar values or vectors of equal length. ## @end item ## ## @item ## @var{lat2}, @var{lon2}, @var{r2}: latitude, longitude, and range of the ## small circle. These must be scalar values or vectors of equal length. ## @end item ## ## @item ## @var{angleUnit}: string for angular units ('degrees' or 'radians', ## case-insensitive, just the first character will do). Default is 'degrees'. ## @var{angleUnit} applies to all inputs and outputs. ## @end item ## @end itemize ## ## Output ## @item ## @var{lat} and @var{lon} are both 1x2 vectors ## @end item ## ## Example ## @example ## [newlat, newlon] = gcxsc (60, 25, 20, 55, 25, 2.5) ## newlat = ## 53.806 57.286 ## newlon = ## 21.226 23.182 ## @end example ## @seealso{gc2sc, gcxgc, scxsc} ## @end deftypefn function [lat, lon] = gcxsc (varargin) if (nargin < 6) print_usage(); elseif (nargin == 6) angleUnit = "degrees"; else angleUnit = varargin{7}; endif if (! (all (cellfun ("isnumeric", varargin(1:6)) && ... all (cellfun ("isreal", varargin(1:6)))))) error ("gcxsc: numeric values expected for first six inputs"); endif vect = [varargin{1:6}]; if (! ischar (angleUnit)) error ("gcxsc: character value expected for 'angleUnit'"); elseif (strncmpi (angleUnit, "degrees", min (length (angleUnit), 7))) ## Latitude must be within (-90, 90) if (any (abs (vect(:, [1 4])) >= 90)) error("gcxsc: latitude value(s) out of acceptable range (-90, 90)") endif vect = deg2rad (vect); elseif (strncmpi (angleUnit, "radians", min (length (angleUnit), 7))) ## Latitude must be within (-pi/2, pi/2) as azimuth isn't defined there if (any (abs (vect(:, [1 4])) >= pi / 2)) error("gcxsc: latitude value(s) out of acceptable range (-pi/2, pi/2)") endif else error ("gcxsc: illegal input for 'angleUnit'"); endif [slat, slong, srg] = gc2sc (vect(1), vect(2), vect(3), "r"); [lat, lon] = scxsc (slat, slong, srg, vect(4), vect(5), vect(6), "r"); if (strncmpi (angleUnit, "degrees", length (angleUnit))) lat = rad2deg (lat); lon = rad2deg (lon); endif endfunction %!test %! [lat, lon] = gcxsc (60, 25, 20, 55, 25, 2.5); %! assert (lat(1), 53.80564992, 1e-6); %! assert (lon(1), 21.22598692, 1e-6); %!error gcxsc ("s", 0, 100, 10, 30, 0) %!error gcxsc (3i, 0, 100, 10, 30, 0) %!error gcxsc (50, "s", 100, 10, 30, 0) %!error gcxsc (50, 2i, 10, 10, 30, 0) %!error gcxsc (50, 0, "s", 10, 30, 0) %!error gcxsc (50, 0, 100i, 10, 30, 0) %!error gcxsc (50, 0, 100, "s", 30, 0) %!error gcxsc (50, 0, 100, 10i, 30, 0) %!error gcxsc (50, 0, 100, 10, "s", 0) %!error gcxsc (50, 0, 100, 10, 30i, 0) %!error gcxsc (50, 0, 100, 10, 30, "s") %!error gcxsc (50, 0, 100, 10, 30, 2i) %!error gcxsc (50, 0, 100, 10, 30, 0, "f") %!error gcxsc (50, 0, 100, 10, 30, 0, "degreef") %!error gcxsc (190, 0, 90, -90.000001, 180, 80); %!error gcxsc (190, 0, -90.001, -90.000001, 180, 80); %!error gcxsc (pi/1.999, 0, pi/2, pi/2.0001, 2, 2*pi/3, "r");