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cultpenguin
@@ -2,11 +2,17 @@
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A python module for reading/writing/manipuating
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SEG-Y formatted filed
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segy.version : The version of SegyPY
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segy.verbose : Amount of verbose information to the screen.
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segy.getValue : Get a value from a binary string
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segy.getSegyHeader : Get SEGY header form file
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segy.readSegy : Read SEGY file
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segy.getSegyHeader : Get SEGY header
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segy.getSegyTraceHeader : Get SEGY Trace header
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segy.getAllSegyTraceHeaders : Get all SEGY Trace headers
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segy.getSegyTrace : Get SEGY Trace heder and trace data for one trace
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segy.getValue : Get a value from a binary string
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segy.ibm2ieee : Convert IBM floats to IEEE
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segy.version : The version of SegyPY
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segy.verbose : Amount of verbose information to the scree
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"""
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#
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# segypy : A Python module for reading and writing SEG-Y formatted data
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@@ -18,7 +24,7 @@ segy.readSegy : Read SEGY file
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import struct
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pref_numeric_module='numarray' # FAST ON LARGE FILES
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pref_numeric_module='Numeric'
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#pref_numeric_module='Numeric'
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if (pref_numeric_module=='Numeric'):
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# IMPORT SEPCIFIC FUNCTIONS FROM Numeric
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print('SegyPY : Using Numeric module')
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@@ -33,10 +39,10 @@ else:
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from numarray import zeros
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# SOME GLOBAL PARAMETERS
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version=0.1
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version=0.2
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verbose=3;
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#endian='>' # Big Endian
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endian='>' # Big Endian
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#endian='<' # Little Endian
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#endian='=' # Native
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@@ -336,18 +342,21 @@ def getSegyTraceHeader(SH,THN='cdp',data='none'):
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for itrace in range(1,ntraces+1,1):
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i=itrace
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pos=THpos+3600+(SH["ns"]*4+240)*(itrace-1);
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pos=THpos+3600+(SH["ns"]*4+240)*(itrace-1);
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txt="Reading trace header " + THN + " " + str(itrace) + " of " + str(ntraces) + " " +str(pos)
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printverbose(txt,10);
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thv[itrace-1],index = getValue(data,pos,THformat,'>',1)
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txt="getSegyTraceHeader : Reading trace header " + THN + " " + str(itrace) + " of " + str(ntraces) + " " +str(pos)
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printverbose(txt,20);
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thv[itrace-1],index = getValue(data,pos,THformat,endian,1)
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txt="getSegyTraceHeader : " + THN + "=" + str(thv[itrace-1])
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printverbose(txt,30);
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return thv
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def getAllSegyTraceHeaders(SH,data='none'):
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SegyTraceHeaders = {'filename': SH["filename"]}
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printverbose('getAllSegyTraceHeaders : trying to get all segy trace headers',2)
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if (data=='none'):
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@@ -357,68 +366,64 @@ def getAllSegyTraceHeaders(SH,data='none'):
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sth = getSegyTraceHeader(SH,key,data)
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SegyTraceHeaders[key]=sth
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txt = "getAllSegyTraceHeaders : " + key
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printverbose(txt,10)
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return SegyTraceHeaders
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return SegyTraceHeaders
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def readSegy(filename) :
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"""
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Data,SegyHeader,SegyTraceHeaders=getSegyHeader(filename)
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"""
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"""
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printverbose("readSegy : Trying to read "+filename,0)
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data = open(filename).read()
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filesize=len(data)
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filesize=len(data)
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SH=getSegyHeader(filename)
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ntraces = (filesize-3600)/(SH['ns']*4+240)
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printverbose("readSegy : Length of data : " + str(filesize),2)
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SH["ntraces"]=ntraces;
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ndummy_samples=240/4
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ndummy_samples=240/4
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printverbose("readSegy : ntraces=" + str(ntraces) + " nsamples="+str(SH['ns']),2)
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index=3600
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Data = zeros((SH['ns'],ntraces))
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index=3600
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# GET TRACE
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index=3200;
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nd=(filesize-3200)/4
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nd=(filesize-3200)/4
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# READ ALL SEGY TRACE HEADRES
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SegyTraceHeaders = getAllSegyTraceHeaders(SH,data)
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printverbose("readSegy : reading data",2)
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# READ ALL DATA EXCEPT FOR SEGY HEADER
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#Data = zeros((SH['ns'],ntraces))
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Data1 = getValue(data,index,'float','>',nd)
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Data1 = getValue(data,index,'float',endian,nd)
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Data = Data1[0]
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#Data=transpose(resize(Data[0:(ntraces*(SH['ns']+60))],(ntraces,SH['ns']+60)))
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# STRIP THE HEADER VALUES FROM THE DATA
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# STRIP THE HEADER VALUES FROM THE DATA
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#
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Data=Data[ndummy_samples:(SH['ns']+60)][:]
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printverbose("readSegyFast : read data",2)
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return Data,SH,SegyTraceHeaders
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def readSegy(filename):
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def readSegyOld(filename):
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"""
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Data,SegyHeader,SegyTraceHeaders=getSegyHeader(filename)
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"""
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#from numarray import *
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Data,SegyHeader,SegyTraceHeaders=readSegyOld(filename)
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"""
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@@ -443,7 +448,7 @@ def readSegy(filename):
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printverbose("readSegy : reading data",2)
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for itrace in range(1,ntraces,1):
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for itrace in range(1,ntraces,1):
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i=itrace
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print "Reading trace ",itrace," of ",ntraces
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SegyTraceHeader,SegyTraceData=getSegyTrace(SH,itrace)
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@@ -475,7 +480,7 @@ def getSegyTrace(SH,itrace):
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SegyTraceHeader=[];
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#print index
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# GET TRACE
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# GET TRACE
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index=3200+(itrace-1)*(240+SH['ns']*4)+240
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SegyTraceData = getValue(data,index,'float',endian,SH['ns'])
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return SegyTraceHeader,SegyTraceData
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@@ -489,7 +494,7 @@ def getSegyHeader(filename):
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SegyHeader = {'filename': filename}
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for key in SH_def.keys():
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pos=SH_def[key]["pos"]
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format=SH_def[key]["type"]
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format=SH_def[key]["type"]
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SegyHeader[key],index = getValue(data,pos,format,endian);
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@@ -503,67 +508,6 @@ def getSegyHeader(filename):
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printverbose('getSegyHeader : succesfully read '+filename,1)
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return SegyHeader
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def getSegyHeader2(filename):
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"""
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SegyHeader=getSegyHeader(filename)
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"""
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data = open(filename).read()
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printverbose('getSegyHeader : trying to read from '+filename,1)
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# START INDEX IN FILE
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index=0;
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SegyHeader = {'filename': filename}
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TextualFileHeader,index = getValue(data,index,'c','>',3200);
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SegyHeader['Job'],index = getValue(data,index,'l','>');
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SegyHeader['Line'],index = getValue(data,index,'l','>')
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SegyHeader['Reel'],index = getValue(data,index,'l','>')
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SegyHeader['DataTracePerEnsemble'],index = getValue(data,index,'h','>')
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SegyHeader['AuxiliaryTracePerEnsemble'],index = getValue(data,index,'short','>')
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SegyHeader['dt'],index = getValue(data,index,'uint16');
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SegyHeader['dtOrig'],index = getValue(data,index,'uint16');
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SegyHeader['ns'],index = getValue(data,index,'uint16');
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SegyHeader['nsOrig'],index = getValue(data,index,'uint16');
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SegyHeader['DataSampleFormat'],index = getValue(data,index,'int16');
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SegyHeader['EnsembleFold'],index = getValue(data,index,'int16');
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SegyHeader['TraceSorting'],index = getValue(data,index,'int16');
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SegyHeader['VerticalSumCode'],index = getValue(data,index,'int16');
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SegyHeader['SweepFrequencyStart'],index = getValue(data,index,'int16');
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SegyHeader['SweepFrequencyEnd'],index = getValue(data,index,'int16');
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SegyHeader['SweepLength'],index = getValue(data,index,'int16');
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SegyHeader['SweepType'],index = getValue(data,index,'int16');
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SegyHeader['SweepChannel'],index = getValue(data,index,'int16');
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SegyHeader['SweepTaperlengthStart'],index = getValue(data,index,'int16');
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SegyHeader['SweepTaperLengthEnd'],index = getValue(data,index,'int16');
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SegyHeader['TaperType'],index = getValue(data,index,'int16');
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SegyHeader['CorrelatedDataTraces'],index = getValue(data,index,'int16');
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SegyHeader['BinaryGain'],index = getValue(data,index,'int16');
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SegyHeader['AmplitudeRecoveryMethod'],index = getValue(data,index,'int16');
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SegyHeader['MeasurementSystem'],index = getValue(data,index,'int16');
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SegyHeader['ImpulseSignalPolarity'],index = getValue(data,index,'int16');
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SegyHeader['VibratoryPolarityCode'],index = getValue(data,index,'int16');
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index=3500;
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SegyHeader['SegyFormatRevisionNumber'],index= getValue(data,index,'uint16');
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SegyHeader['FixedLengthTraceFlag'],index=getValue(data,index,'uint16');
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SegyHeader['NumberOfExtTextualHeaders'],index= getValue(data,index,'uint16');
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# CALCULATE NUMBER OF TRACES
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filesize=len(data)
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ntraces = (filesize-3600)/(SegyHeader['ns']*4+240)
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SegyHeader["ntraces"]=ntraces;
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printverbose('getSegyHeader : succesfully read '+filename,1)
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return SegyHeader
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@@ -594,20 +538,23 @@ def getValue(data,index,ctype='l',endian='>',number=1):
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size=l_float
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ctype='f'
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else:
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printverbose('Bad Ctype : ' +ctype,-1)
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cformat=endian + ctype*number
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cformat=endian + ctype*number
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printverbose('getValue : cformat : ' + cformat,40)
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index_end=index+size*number
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Value=struct.unpack(cformat, data[index:index_end])
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# IF READING IBM FLOATING DATA
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HeaderValue=struct.unpack(cformat, data[index:index_end])
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#Value = ibm2ieee(data[index:index_end])
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vtxt = 'getValue : '+'start='+str(index)+' size='+str(size)+ ' number='+str(number)+' Value='+str(Value)+' cformat='+str(cformat)
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printverbose(vtxt,20)
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if number==1:
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return HeaderValue[0], index_end
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return Value[0], index_end
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else:
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return Value,index_end
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@@ -618,6 +565,17 @@ def printverbose(txt,level=1):
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def printverbose(txt,level=1):
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if level<verbose:
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print 'SegyPY',version,': ',txt
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##############
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# MISC FUNCTIONS
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def ibm2ieee(ibm_float):
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i = struct.unpack('>I',ibm_float[0])
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sign = [1,-1][bool(i & 0x100000000L)]
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characteristic = ((i >> 24) & 0x7f) - 64
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fraction = (i & 0xffffff)/float(0x1000000L)
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return sign*16**characteristic*fraction
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##############
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+5
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@@ -6,17 +6,16 @@ import struct
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import segypy
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filename='mini.sgy'
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data = open(filename).read()
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#data = open(filename).read()
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# reading SEG-Y header
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SH=segypy.getSegyHeader(filename)
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print SH
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print SH['Reel']
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#SH=segypy.getSegyHeader(filename)
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#print SH
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#print SH['Reel']
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# Set verbose level
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segypy.verbose=1;
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# Read Segy File
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#Data,SH,STH=segypy.readSegyFast(filename);
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Data,SH,STH=segypy.readSegy(filename);
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