function []=timespan(wie)
% -----------------------------------------------------------------------------
% GPSLab:     TIMESPAN(w)       
%             mit      w=1,2,3
%
% Zeitspanne/Ausschnitt aus simultanen Daten von Referenz und Rover w鋒len:
% numerisch (w=1), graphisch (w=2), zur點k zu voller Zeitspanne (w=3)
% Bei der Wahl w=1 kann unter Nutzung von CANCEL auch nur eingesehen werden.
%
% Bearbeitet die folgenden Dateien: s1l1,s1l2,s1p1,s1p2,s1c1,s1epo
%                                   s2l1,s2l2,s2p1,s2p2,s2c1,s2epo
% und erstellt Backup-Dateien unter demselben Namen, nur mit der Endung *.org
%
% Utility nur f黵 den Gebrauch im Zusammenhang mit GPSLab und dessen Dateistruktur
%
% -----------------------------------------------------------------------------
% GPSLab (c) iapg 1998,1999 zeb   - Version 09-99

% neu (bei voller Kompatibilit鋞) gegen黚er 07-99:
% * Check, ob 黚erhaupt simultane Daten vorhanden
% * Darstellung des simultanen Bereichs f黵 Referenz und Rover

% GPSLab (c) iapg 1997,1998,1999,2000,2001 zeb   - Version 12-99 R-04-01-e
% -----------------------------------------------------------------------------
% Letzte Aenderung 2001-04-13: 
% Der DOS-Befehl MOVE unter NT erlaubt kein Ueberschreiben. 
% Daher muss vorher die jeweilige Datei mit DEL geloescht werden.
% -----------------------------------------------------------------------------


if nargin==0
   wie=1;
end

if wie~=1&wie~=2&wie~=3
   errordlg('Only options 1, 2 or 3 are valid');
end


% Fallunterscheidung:
% -------------------

% Wiederherstellen der urspr黱glichen Dateien (zur點k zu voller Spanne)

if wie==3    
   if exist('s2epo.org')==2
      dos('del s2epo |');      % f黵 ROVER-Dateien
      dos('del s2c1 |');
      dos('del s2p1 |');
      dos('del s2p2 |');
      dos('del s2l1 |');
      dos('del s2l2 |');
      
      dos('del s1epo |');      % f黵 REFERENZ-Dateien
      dos('del s1c1 |');
      dos('del s1p1 |');
      dos('del s1p2 |');
      dos('del s1l1 |');
      dos('del s1l2 |');
      
      dos('move s2epo.org s2epo |');      % f黵 ROVER-Dateien
      dos('move s2c1.org s2c1 |');
      dos('move s2p1.org s2p1 |');
      dos('move s2p2.org s2p2 |');
      dos('move s2l1.org s2l1 |');
      dos('move s2l2.org s2l2 |');
      
      dos('move s1epo.org s1epo |');      % f黵 REFERENZ-Dateien
      dos('move s1c1.org s1c1 |');
      dos('move s1p1.org s1p1 |');
      dos('move s1p2.org s1p2 |');
      dos('move s1l1.org s1l1 |');
      dos('move s1l2.org s1l2 |');

      load s1epo;
      load s2epo;
     
      s1min=min(s1epo(:,1));
      s1max=max(s1epo(:,1));
      s2min=min(s2epo(:,1));
      s2max=max(s2epo(:,1));

      figure(99)
      subplot(2,1,1);

      plot(s1epo(:,1),s1epo(:,2:13),'sb');
      axis([max(s1min,s2min) min(s1max,s2max) 1 32]);

      colormap cool;
      title('simultaneous observations - original files');
      ylabel('PRN numbers of the satellites');
      xlabel('above: observations at reference station');
      grid;

      subplot(2,1,2);

      plot(s2epo(:,1),s2epo(:,2:13),'sb');
      axis([max(s1min,s2min) min(s1max,s2max) 1 32]);

      colormap cool;
      title('below: observations at rover station');
      ylabel('PRN numbers of the satellites');
      xlabel('observation time in GPS week seconds');
      grid;
   
      gpsjpg=imread('sat.jpg','JPEG');
      hmsg=msgbox(['The files of REFERENCE and ROVER related to the original (full) timespan' ...
      ' have been reconstructed (Epoch, Code and Carrier Phase files).'], ...
      'GPSLab Info: Timespan Reset','custom',gpsjpg,summer(64));
      clear gpsjpg;
   else
       errordlg(['Error occurring in program TIMESPAN.M while searching the original set of files.',...
       ' They seem to be unchanged, i.e. there was no cut created.' ...
       ' In the other case you have to re-generate the files from RINEX.'], ...   
       'GPSLab: Break');
   end
   return;
end

% Anzeige in den F鋖len 1 und 2

load s1epo;
load s2epo;

s1min=min(s1epo(:,1));
s1max=max(s1epo(:,1));
s2min=min(s2epo(:,1));
s2max=max(s2epo(:,1));

if max(s1min,s2min)>min(s1max,s2max)
         gpsjpg=imread('sat.jpg','JPEG');
      hmsg=msgbox(['The files of REFERENCE and ROVER contain data from different periods,' ...
      ' which do not overlap. Please load the corresponding files to enable a DGPS/CDGPS processing.'], ...
      'GPSLab Info: Attention - No simultaneous observations ! ','custom',gpsjpg,summer(64));
   clear gpsjpg;
   return;
end

figure(99)
subplot(2,1,1);

plot(s1epo(:,1),s1epo(:,2:13),'sb');
axis([max(s1min,s2min) min(s1max,s2max) 1 32]);

colormap cool;
      title('simultaneous observations');
      ylabel('PRN numbers of the satellites');
      xlabel('above: observations at reference station');
grid;

subplot(2,1,2);

plot(s2epo(:,1),s2epo(:,2:13),'sb');
axis([max(s1min,s2min) min(s1max,s2max) 1 32]);

colormap cool;
      title('below: observations at rover station');
      ylabel('PRN numbers of the satellites');
      xlabel('observation time in GPS week seconds');
grid;

% Wahl des Ausschnitts:

% numerisch / bzw. nur Anzeige (Cancel)

if wie==1      

prompt={'Start in [GPS week seconds]','End in [GPS week seconds]'};
def={num2str(min(s2epo(:,1))),num2str(max(s2epo(:,1)))};
titel='GPS Lab: Select timespan';
lineNo=[1;1];
answer=inputdlg(prompt,titel,lineNo,def);


if size(answer)==[0 0] % Der Fall, da