writesegy.m

基于matlab的反演程序,用于地球物理勘探中射线追踪及偏移成像程序.

function code=writesegy(filename,line_name,seis,x,t,nullval,ntr,...
		xs,ys,xr,yr,offs, selevs,relevs,sdepths,cdps)

% code=writesegy(filename,line_name,seis,x,t,nullval,ntr,...
%		xs,ys,xr,yr,offs,selevs,relevs,sdepths,cdps)
%
% FMSEGYOUT writes a fleximat to disk in SEGY format.
%
%	filename ... full file name to write to
%	line_name ... line name
%	seis ... matrix containing the seismic. one trace per column
%	x ... vector of x coordinates for seis. One per column.
%	t ... vector of time coordinates for seis. One per row.
%	nullval ... numerica value to replace nans with
%	*** default is 0.0 ***
%	ntr ... number of traces per gather in the output dataset
%	*** default is 24 ***
%	xs ... inline source coordinates for each trace in fmseis
%	*** default is the x coordinates in fmseis ***
%	ys ... crossline source coordinates for each trace in fmseis
%	*** default is all zeros ***
%	xr ... inline receiver coordinates for each trace in fmseis
%	*** default is the x coordinates in fmseis ***
%	yr ... crossline receiver coordinates for each trace in fmseis
%	*** default is all zeros ***
%	offs ... s-r offsets for each trace in fmseis
%	*** default is all zeros ***
%	selevs ... source elevation for each trace in fmseis
%	*** default is all zeros ***
%	relevs ... receiver elevation for each trace in fmseis
%	*** default is all zeros ***
%	sdepths ... source depths for each trace in fmseis
%	*** default is all zeros ***
%	cdps ... cdp numbers for each trace in fmseis
%	*** default 1:num_traces_in_fmseis ***
%
%	code is 1 for a successful write and 0 otherwise
%
% Note that the defaults are appropriate for writting a simple
%	post stack dataset.
%
% NOTE: It is illegal for you to use this software for a purpose other
% than non-profit education or research UNLESS you are employed by a CREWES
% Project sponsor. By using this software, you are agreeing to the terms
% detailed in this software's Matlab source file.
 
% BEGIN TERMS OF USE LICENSE
%
% This SOFTWARE is maintained by the CREWES Project at the Department
% of Geology and Geophysics of the University of Calgary, Calgary,
% Alberta, Canada.  The copyright and ownership is jointly held by 
% its author (identified above) and the CREWES Project.  The CREWES 
% project may be contacted via email at:  [e-mail]
% 
% The term 'SOFTWARE' refers to the Matlab source code, translations to
% any other computer language, or object code
%
% Terms of use of this SOFTWARE
%
% 1) Use of this SOFTWARE by any for-profit commercial organization is
%    expressly forbidden unless said organization is a CREWES Project
%    Sponsor.
%
% 2) A CREWES Project sponsor may use this SOFTWARE under the terms of the 
%    CREWES Project Sponsorship agreement.
%
% 3) A student or employee of a non-profit educational institution may 
%    use this SOFTWARE subject to the following terms and conditions:
%    - this SOFTWARE is for teaching or research purposes only.
%    - this SOFTWARE may be distributed to other students or researchers 
%      provided that these license terms are included.
%    - reselling the SOFTWARE, or including it or any portion of it, in any
%      software that will be resold is expressly forbidden.
%    - transfering the SOFTWARE in any form to a commercial firm or any 
%      other for-profit organization is expressly forbidden.
%
% END TERMS OF USE LICENSE


if(nargin<16) cdps=1:length(x); end
if(nargin<15) sdepths = zeros(size(x)); end
if(nargin<14) relevs = zeros(size(x)); end
if(nargin<13) selevs = zeros(size(x)); end
if(nargin<12) offs = zeros(size(x)); end
if(nargin<11) yr = zeros(size(x)); end
if(nargin<10) xr = x; end
if(nargin<9) ys = zeros(size(x)); end
if(nargin<8) xs = x; end
if(nargin<7) ntr=24; end
if(nargin<6) nullval=0.0; end

nsamp=length(t);
dt=t(2)-t(1);
ntrace=length(x);
nrec=ceil(ntrace/ntr);

%open the file and write out the master header
fid=segyout_open(filename,line_name,nsamp,dt,ntr,nrec);
if(fid==-1)
	code=0;
	return;
end

%replace nans
ind=find(isnan(seis));
seis(ind)=nullval*ones(size(ind));

%loop over traces and write each
for k=1:ntrace
	itr=rem(k-1,ntr)+1;
	irec=ceil(k/ntr);
	segyout(fid,seis(:,k),k,itr,irec,dt,offs(k),sdepths(k),...
		selevs(k),relevs(k),xs(k),ys(k),xr(k),yr(k),cdps(k));
end

fclose(fid);

code=1;