xecef2~1.m

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%                             xecef2gd_comp.m
%  Scope:   This MATLAB program performs the comparison between two different 
%           algorithms implementing the ECEF to Geodetic coordinates 
%           transformation; WGS-84 constants are used.
%  Usage:   xecef2gd_comp
%  Inputs:  - name of the output file if selected (the default is the screen)
%           - input data from the keyboard as follows:
%              - x-component of the ECEF position, in meters 
%              - y-component of the ECEF position, in meters 
%              - z-component of the ECEF position, in meters 
%              The ECEF coordinates can be entered from keyboard or from a
%              specified file (in this case the record contains the
%              x, y, and z components)
%  Outputs: - input/output data stored into the specified output file or
%             displayed on screen
%  External Matlab macros used:  tecefgd, tecefgd2, wgs84con
%  Last update:  05/08/00
%  Copyright (C) 1996-00 by LL Consulting. All Rights Reserved.

clear  

yes = 'y';

disp('  ');
answer1 = input('Do you want to save the results? (y/n)[n] --> ','s');
disp('  ');
if (strcmp(answer1,yes) == 1)
   f2 = input('Specify the output filename  -->  ','s');
   disp('  ');
else
   f2 = 1;      %  output to the screen
end

disp('Execute ECEF to Geodetic Transformation by using 2 different algorithms');
disp('  ');

ntrials = input('Enter number of trials, e.g. 1000, --> ');
disp('  ');

answer2 = input('Enter data from keyboard? (y/n)[n] --> ','s');
disp('  ');

if (strcmp(answer2,yes) == 1)  
   pecef(1) = input('Enter ECEF x-component in meters --> ');   
   pecef(2) = input('Enter ECEF y-component in meters --> ');   
   pecef(3) = input('Enter ECEF z-component in meters --> ');   
   disp('  ');
else   
   finp = input('Specify input filename --> ','s');
   disp('  ');

%  Read the input data file

   pecef = load(finp);
   [nrow,ncol] = size(tt);
   if  ncol ~= 3
       error('Error - Xexef2gd_comp; check the input data file');
   end
end

%  Compute Geodetic coordinates by using macro  tecefgd

tic;
for k = 1:ntrials
   [lat1,lon1,alt1] = tecefgd(pecef);
end
etime1 = toc;

%  Compute Geodetic coordinates by using macro  tecefgd2

tic;
for k = 1:ntrials
   [lat2,lon2,alt2] = tecefgd2(pecef);
end
etime2 = toc;

%  Save the results if the output file is specified or display on screen

fprintf(f2,'\n**************************************************');
fprintf(f2,'******************************\n');
fprintf(f2,'\n*****   ECEF coordinates   *****\n');
fprintf(f2,'      x - component         y - component');
fprintf(f2,'         z - component   \n');
fprintf(f2,'%20.7f  %20.7f  %20.7f\n', pecef(1),pecef(2),pecef(3));
fprintf(f2,'\n*****   Geodetic coordinates by using  tecefgd   *****\n');
fprintf(f2,'      latitude (rad.)       longitude (rad.)');
fprintf(f2,'      altitude (m.)   \n');
fprintf(f2,'%20.12f  %20.12f  %20.12f\n',lat1,lon1,alt1);
fprintf(f2,'Elapsed time = %20.12f  seconds\n',etime1/ntrials);
fprintf(f2,'\n*****   Geodetic coordinates by using  tecefgd2  *****\n');
fprintf(f2,'      latitude (rad.)       longitude (rad.)');
fprintf(f2,'      altitude (m.)   \n');
fprintf(f2,'%20.12f  %20.12f  %20.12f\n',lat2,lon2,alt2);
fprintf(f2,'Elapsed time = %20.12f  seconds\n',etime2/ntrials);
fprintf(f2,'\n**************************************************');
fprintf(f2,'******************************\n');

disp('  ');
disp('End of the program  Xecef2gd_comp');
disp('  ');