commit 333130f6ade684aebfd1f33fc31a1aac00945884
Author: cultpenguin <none@none>
Date:   Thu Apr 14 05:25:07 2005 +0000

    Initial revision

diff --git a/segypy.py b/segypy.py
new file mode 100644
index 0000000..35fbc36
--- /dev/null
+++ b/segypy.py
@@ -0,0 +1,207 @@
+"""
+A python module for reading/writing/manipuating 
+SEG-Y formatted filed
+
+segy.segypy_version : The version of SegyPY
+segy.segypy_verbose : A,punt of verbose information to the screen.
+segy.getValue : Get a value from a binary string
+
+"""
+#
+# segypy : A Python module for reading and writing SEG-Y formatted data
+#
+# (C) Thomas Mejer Hansen, 2005
+
+import struct
+
+# SOME GLOBAL PARAMETERS
+segypy_version=0.1
+segypy_verbose=10;
+
+#endian='>' # Big Endian
+#endian='<' # Little Endian
+#endian='=' # Native
+
+
+l_long = struct.calcsize('l')
+l_ulong = struct.calcsize('L')
+l_short = struct.calcsize('h')
+l_ushort = struct.calcsize('H')
+l_char = struct.calcsize('c')
+l_uchar = struct.calcsize('B')
+l_float = struct.calcsize('f')
+
+def readSegy(filename):
+	"""
+	getSegyHeader
+	"""
+	from pylab import *
+	data = open(filename).read()
+
+	filesize=len(data)
+        vtxt = 'Length of data ; ',filesize
+	printverbose(vtxt,2)
+
+	SH=getSegyHeader(filename)
+
+	ntraces = (filesize-3600)/(SH['ns']*4+240)
+	printverbose(vtxt,2)
+
+        vtxt = "readSegy :  ntraces=",ntraces,"nsamples=",SH['ns']
+	printverbose(vtxt,2)
+
+	index=3600
+
+
+	# ntraces=500;
+	Data = zeros((SH['ns'],ntraces))
+
+	printverbose("readSegy :  reading data",2)
+
+	for itrace in range(1,ntraces,1):
+		i=itrace
+#		print "Reading trace ",itrace," of ",ntraces
+		SegyTraceHeader,SegyTraceData=getSegyTrace(SH,itrace)
+       
+		for iss in range(1,SH['ns'],1):
+			Data[iss-1][itrace-1]=SegyTraceData[0][iss-1]
+ 		   
+	printverbose("readSegy :  read data",2)
+	
+	if (segypy_verbose>2):
+		imshow(Data)
+		title('pymat test')
+		grid(True)
+		show()
+
+
+	return Data,SH
+
+def getSegyTrace(SH,itrace):
+	data = open(SH["filename"]).read()
+	# GET TRACE HEADER
+	index=3200+(itrace-1)*(240+SH['ns']*4)
+	SegyTraceHeader=[];
+	#print index
+
+	# GET TRACE
+	index=3200+(itrace-1)*(240+SH['ns']*4)+240
+	SegyTraceData = getValue(data,index,'float','>',SH['ns'])
+	return SegyTraceHeader,SegyTraceData
+
+
+def getSegyHeader(filename,offset=3200):
+
+	data = open(filename).read()
+
+        printverbose('getSegyHeader : trying to read from '+filename,1)
+	
+	# START INDEX IN FILE
+	index=offset;
+	index=0;
+
+	SegyHeader = {'filename': filename}
+
+	TextualFileHeader,index = getValue(data,index,'c','>',3200);
+
+	SegyHeader['Job'],index = getValue(data,index,'l','>');	
+	SegyHeader['Line'],index = getValue(data,index,'l','>')
+	SegyHeader['Reel'],index = getValue(data,index,'l','>')
+	SegyHeader['DataTracePerEnsemble'],index = getValue(data,index,'h','>')
+	SegyHeader['AuxiliaryTracePerEnsemble'],index = getValue(data,index,'short','>')
+	SegyHeader['dt'],index = getValue(data,index,'uint16');
+	SegyHeader['dtOrig'],index = getValue(data,index,'uint16'); 
+	SegyHeader['ns'],index = getValue(data,index,'uint16');       
+	SegyHeader['nsOrig'],index = getValue(data,index,'uint16');
+	SegyHeader['DataSampleFormat'],index = getValue(data,index,'int16'); 
+	SegyHeader['EnsembleFold'],index = getValue(data,index,'int16');                
+	SegyHeader['TraceSorting'],index = getValue(data,index,'int16');              
+	SegyHeader['VerticalSumCode'],index = getValue(data,index,'int16');      
+
+	SegyHeader['SweepFrequencyStart'],index = getValue(data,index,'int16');   
+	SegyHeader['SweepFrequencyEnd'],index = getValue(data,index,'int16');    
+	SegyHeader['SweepLength'],index = getValue(data,index,'int16');                
+	SegyHeader['SweepType'],index = getValue(data,index,'int16');                 
+	SegyHeader['SweepChannel'],index = getValue(data,index,'int16');           
+	SegyHeader['SweepTaperlengthStart'],index = getValue(data,index,'int16');             
+	SegyHeader['SweepTaperLengthEnd'],index = getValue(data,index,'int16');              
+	SegyHeader['TaperType'],index = getValue(data,index,'int16');              
+	SegyHeader['CorrelatedDataTraces'],index = getValue(data,index,'int16');
+	SegyHeader['BinaryGain'],index = getValue(data,index,'int16');             
+	SegyHeader['AmplitudeRecoveryMethod'],index = getValue(data,index,'int16');
+	SegyHeader['MeasurementSystem'],index = getValue(data,index,'int16');      
+	SegyHeader['ImpulseSignalPolarity'],index = getValue(data,index,'int16');     
+	SegyHeader['VibratoryPolarityCode'],index = getValue(data,index,'int16');             
+
+	index=3500;
+	SegyHeader['SegyFormatRevisionNumber'],index= getValue(data,index,'uint16');  
+	SegyHeader['FixedLengthTraceFlag'],index=getValue(data,index,'uint16');        
+	SegyHeader['NumberOfExtTextualHeaders'],index= getValue(data,index,'uint16');
+
+        printverbose('getSegyHeader : succesfully read '+filename,1)
+
+	return SegyHeader
+
+
+
+def getValue(data,index,ctype='l',endian='>',number=1):
+	"""
+	GET
+	"""
+	if (ctype=='l')|(ctype=='long'):
+		size=l_long
+	        ctype='l'
+        elif (ctype=='L')|(ctype=='ulong'):
+		size=l_ulong
+		ctype='L'
+        elif (ctype=='h')|(ctype=='short')|(ctype=='int16'):
+		size=l_short
+		ctype='h'
+        elif (ctype=='H')|(ctype=='ushort')|(ctype=='uint16'):
+		size=l_ushort
+		ctype='H'
+        elif (ctype=='c')|(ctype=='char'):
+		size=l_char
+		ctype='c'
+        elif (ctype=='B')|(ctype=='uchar'):
+		size=l_uchar
+		ctype='B'
+        elif (ctype=='f')|(ctype=='float'):
+		size=l_float
+		ctype='f'
+	else:
+		printverbose('Bad Ctype : ' +ctype,-1)
+
+	cformat=endian + ctype*number
+
+	printverbose('cformat :  ' + cformat,20)
+	
+	index_end=index+size*number
+	HeaderValue=struct.unpack(cformat, data[index:index_end])
+	
+	str = 'getSegyHeaderValue','start=',index,' size=',size, 'number=',number,'Value=',HeaderValue,'cformat=',cformat
+        printverbose(str,20)
+
+	if number==1:
+		return HeaderValue[0], index_end
+	else:
+		return HeaderValue,index_end
+
+
+def version():
+	return segypy_version
+
+def print_version():
+	print 'SegyPY version is ', segypy_version
+
+def printverbose(txt,level):
+        if level<segypy_verbose:
+		print 'SegyPY',segypy_version,': ',txt
+
+
+
+#def read(filename):
+#	read_segy(filename)
+#
+#def write(filename):
+#	write_segy(filename)
diff --git a/testsegy.py b/testsegy.py
new file mode 100644
index 0000000..cb3d880
--- /dev/null
+++ b/testsegy.py
@@ -0,0 +1,42 @@
+#
+#
+# testsegy.py
+#
+import struct
+import segypy
+
+filename='mini.sgy'
+
+data = open(filename).read()
+
+l_long = struct.calcsize('l')
+l_ulong = struct.calcsize('L')
+l_short = struct.calcsize('h')
+l_ushort = struct.calcsize('H')
+
+segypy_version=segypy.version()
+
+print 'filename=',filename
+
+
+#index=3200;
+#Job,size = segypy.getValue(data,index,'l','>')
+#Job,size = segypy.getValue(data,index,'long','>')
+#index=index+size
+#Line,size = segypy.getValue(data,index,'l','>')
+#index =index+size
+#Reel,size = segypy.getValue(data,index,'l','>')
+#index=index+size
+#DataTracePerEnsemble, size = segypy.getValue(data,index,'h','>')
+#DataTracePerEnsemble, size = segypy.getValue(data,index,'short','>')
+
+print "GET SEGY GEADER"
+SH=segypy.getSegyHeader(filename)
+
+print SH
+#print SH['Reel']
+
+print "TESTING READING OF SEGY FILE"
+segypy.readSegy(filename);
+
+