writsegy.m

这是matlab在地球物理数据处理方面的源码

function [out] = writsegy(profile,t,x,filename);

% function [out] = writesegy(profile,t,x,filename) is a simple program
% to write your seismic profile to a segy format file in order for you
% to be able to read it easily in VISTA or other black box seismic processing
% packages.  profile is the data traces to write out must be in time along
% the rows and position along the columns.  t is the timebase (in seconds)
%  which is a vector
% the same length as a column in profile.  x is the position vector (in meters)
% with the same length as a row of profile.  filename is the filename you want
% to write this to.  Note that you must include it as 'filename' with the single
% quotes when written in the function. Example
%      [out] = writsegy(traces,time,offset,'mydata.sgy')
% I strongly suggest you include the .sgy suffix to the file name.
% Note that the data is written out in 4 byte floating point format.
% out is just a flag that tells you how many numbers have been written.
% Copyright D.R. Schmitt, 1998 - Use this program at your own risk.

delt = t(2) - t(1);
fid = fopen(filename,'w');
count = fwrite(fid,['Geophysical Field School - Student Profile - 1998           '],'char');
out = count;
junk = zeros(3140,1);
count = fwrite(fid,junk,'char');  % Write empty ascii header
out = out + count;
[m,n] = size(profile);

% Binary header
junk = [ 1 1  1];  count = fwrite(fid,junk,'long');  %
out = out + count;
junk = [ n 0 delt*1e6 delt*1e6 m  m 1 24 1 1 0 0 0 0 0 0 0 0 0 0 0 1 1 1 ];
count = fwrite(fid,junk,'short');  out = out + count;
junk = zeros(1,170); count = fwrite(fid,junk,'short');  out = out + count;


% Data and trace headers

for i = 1:n

% This section writes the segy headers information - as you might infer
% from this there is a reason I tried to keep it from the class as long as
% possible!

tracehead = [i i i i i i 0 ];
count = fwrite(fid,tracehead,'long');  out = out + count;
tracehead = [1 1 2 1]; count = fwrite(fid,tracehead,'short'); out = out + count;
tracehead = [0 0 0 0 0 0 0 0 ]; count = fwrite(fid,tracehead,'long'); out = out + count;
tracehead = [1 1]; count = fwrite(fid,tracehead,'short');  out = out + count;
tracehead = [i 0 i 0]; count = fwrite(fid,tracehead,'long'); out = out + count;
tracehead = [ 1 0 0 0 0 0 0 0 0 0 0 0 0 m delt*1e6 1 1 1 1];
count = fwrite(fid,tracehead,'short'); out = out + count;
tracehead = [ 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1997 300 0 0 0 1 0 1 1 1 0 0];
count = fwrite(fid,tracehead,'short');  out = out + count;
tracehead = zeros(1,60); count = fwrite(fid,tracehead,'char');  out = out + count;

% This line writes the actual trace data
count = fwrite(fid,profile(:,i),'float');  out = out + count;

end % i

fclose all