function dataout=azimuth(datain)%function dataout=azimuth(datain)%%This program computes the receiver-to-shot azimuth angle%and puts the corresponding angle (in degrees) in header word 9
%%DSI customized VSP processing software%written by Gervais Perron March 4th, 1998%$Id: azimuth.m,v 3.0 2000/06/13 19:19:47 gilles Exp $%$Log: azimuth.m,v $%Revision 3.0  2000/06/13 19:19:47  gilles%Release 3%%Revision 2.0  1999/05/21 18:45:10  mah%Release 2%%Revision 1.1  1999/01/06 19:09:01  kay%Initial revision%%%Copyright (C) 1998 Seismology and Electromagnetic Section/%Continental Geosciences Division/Geological Survey of Canada%%This library is free software; you can redistribute it and/or%modify it under the terms of the GNU Library General Public%License as published by the Free Software Foundation; either%version 2 of the License, or (at your option) any later version.%%This library 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%Library General Public License for more details.%%You should have received a copy of the GNU Library General Public%License along with this library; if not, write to the%Free Software Foundation, Inc., 59 Temple Place - Suite 330,%Boston, MA  02111-1307, USA.%%DSI Consortium%Continental Geosciences Division%Geological Survey of Canada%615 Booth St.%Ottawa, Ontario%K1A 0E9%%email: dsi@cg.nrcan.gc.cadisp('function dataout=azimuth(datain);')dataout=datain;for i=1:datain.fh{12}   for j=1:datain.th{i}(12,1)      diffn=datain.th{i}(29,j)-datain.th{i}(35,j);      diffe=datain.th{i}(31,j)-datain.th{i}(37,j);      dataout.th{i}(53,j)=sqrt(diffn.^2+diffe.^2);      if diffn>=0 & diffe>=0         a=atan(diffn/diffe);         azdeg(j)=90-(a*180/pi);         azrad(j)=azdeg(j)*pi/180;      elseif diffn<=0 & diffe>=0         a=atan(diffn/diffe);         azdeg(j)=90+abs(a*180/pi);         azrad(j)=azdeg(j)*pi/180;      elseif diffn<=0 & diffe<=0         a=atan(diffn/diffe);         azdeg(j)=180+90-(a*180/pi);         azrad(j)=azdeg(j)*pi/180;      elseif diffn>=0 & diffe<=0         a=atan(diffn/diffe);         azdeg(j)=180+90+abs(a*180/pi);         azrad(j)=azdeg(j)*pi/180;      end   end   dataout.th{i}(9,:)=azdeg;   dataout.th{i}(64,:)=azrad;end