readqcd.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 [logname,z,samps,topnames,ztops,kb,units]=readqcd(filename)

% [logname,z,samps,topnames,ztops,kb,units]=readqcd(filename)
%
% READGMA reads a well log and formation tops (if any) from a diskfile 
% which is assumed to be in QCD ascii format.
%
% 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

%open the file
fid=fopen(filename);
if( fid == -1 )
   errst = sprintf('Could not open file %s',filename);
   error(errst);
end

%read the first line

rec=fgetl(fid);

if(length(rec)<59)
	logname=-1;
	return;
end

% get the log name
logname = sscanf(rec(1:28),'%s');

% start depth, end depth, sample rate nsamP
zbeg=sscanf(rec(29:35),'%f');
zend=sscanf(rec(36:43),'%f');
dz=sscanf(rec(46:52),'%f');
%dat=sscanf(rec(29:52),'%f');
%zbeg=dat(1);
%zend=dat(2);
%dz=dat(3);
nz=sscanf(rec(53:59),'%f');
if(isempty(nz));
	nz=20000;
end

%units flag
if(length(rec)>=70)
	units=rec(70);
	if(abs(units)==32)
		units='M';
	end
else
	units='M';
end

ntest=(zend-zbeg)/dz;
if( ntest < 0 | isinf(ntest) | isnan(ntest) | ntest > 100000.)
	logname=-1;
	return;
end

%grab some memory
z=nan*ones(nz+10,1);
samps=z;

%loop to read in samples
if( nz~=20000 )
	disp([int2str(nz) ' samples to read'])
else
	disp('reading samples')
end
rec=fgetl(fid);

ntops=0;
ksamp=0;
while( ksamp<nz & rec ~= -1 )
 %test for enpty line
 if(~isempty(rec))
		% test for onset of tops
		if( strcmp(rec(1:6),'#TOPS#') )
			ntops=sscanf(rec(7:length(rec)),'%d');
			break;
		end
		%test for kb. This is always at the end of the file
		if(strcmp( rec(1:2),'KB') )
			kb=sscanf(rec(3:length(rec)),'%f');
			return;
		end

		% get number of entries on line
		num=sscanf(rec(78:80),'%d');

		znot=sscanf(rec(1:7),'%f');
		for k=1:num
			ksamp=ksamp+1;
			z(ksamp)=znot+(k-1)*dz;
			samps(ksamp)=sscanf(rec(8+(k-1)*7:14+(k-1)*7),'%f');
		end

		if( rem(ksamp,500)==0 )
			disp([int2str(ksamp) ' samples read']);
		end

	end
rec=fgetl(fid);
end

%free up unneeded memory
ind=find(~isnan(z));
z=z(ind);
samps=samps(ind);

if( ~ntops )
	if(rec==-1)
		return;
	else
		%look for tops
		while( rec~= -1)
			if(~isempty(rec))
				if( strcmp(rec(1:6),'#TOPS#') )
					ntops=sscanf(rec(7:length(rec)),'%d');
					break;
				end
				if( strcmp(rec(1:2),'KB') )
					kb=sscanf(rec(3:length(rec)),'%f');
					return;
				end
			end
			rec=fgetl(fid);
		end
	end
end

if( ntops )

	topnames=ones(ntops,30);
	ztops=nan*zeros(ntops,1);

	ktop=0;
	while(ktop < ntops )
		rec=fgetl(fid);
		if(~isempty(rec))
			ktop=ktop+1;
			name=sscanf(rec(1:32),'%s');
			n=min([30 length(name)]);
			topnames(ktop,1:n)=name;

			ztops(ktop)=sscanf(rec(33:length(rec)),'%f');
		end
	end

end

%attempt to read kb
rec=fgetl(fid);
while(rec~=-1)
	if(~isempty(rec))
		if( strcmp(rec(1:2),'KB') )
			kb=sscanf(rec(3:length(rec)),'%f');
		end
	end
	rec=fgetl(fid);
end

fclose(fid);