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cultpenguin
2005-04-21 09:01:54 +00:00
parent 125ffa670f
commit a645b0ea28
1 changed files with 77 additions and 10 deletions
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segypy.py
+77 -10
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@@ -34,7 +34,7 @@ else:
# SOME GLOBAL PARAMETERS
version=0.1
verbose=1;
verbose=3;
#endian='>' # Big Endian
#endian='<' # Little Endian
@@ -56,11 +56,36 @@ l_float = struct.calcsize('f')
# Initialize SEGY HEADER
SH_def = {"Job": {"pos": 3200,"type":"int32"}}
SH_def["Line"]= {"pos": 3204,"type":"int32"}
SH_def["Line"]= {"pos": 3208,"type":"int32"}
SH_def["Reel"]= {"pos": 3208,"type":"int32"}
SH_def["DataTracePerEnsemble"]= {"pos": 3212,"type":"int16"}
SH_def["AuxiliaryTracePerEnsemble"]={"pos": 3214,"type":"int16"}
SH_def["dt"]= {"pos": 3216,"type":"uint16"}
SH_def["dtOrig"]= {"pos": 3218,"type":"uint16"}
SH_def["ns"]={"pos": 3220,"type":"uint16"} #; % 3222
SH_def["nsOrig"]={"pos": 3222,"type":"uint16"} #; % 3224
SH_def["DataSampleFormat"]={"pos": 3224,"type":"int16"} #; % 3226
SH_def["EnsembleFold"]={"pos": 3226,"type":"int16"} #;
SH_def["TraceSorting"]={"pos": 3228,"type":"int16"} #; % 3228
SH_def["VerticalSumCode"]={"pos": 3230,"type":"int16"} #; % 3230␍SH_def["SweepFrequencyStart"]={"pos": 3232,"type":'uint16'} #; % 3232
SH_def["SweepFrequencyEnd"]={"pos": 3234,"type":"int16"} #; % 3234
SH_def["SweepLength"]={"pos": 3236,"type":"int16"} #; % 3236
SH_def["SweepType"]={"pos": 3238,"type":"int16"} #; % 3238
SH_def["SweepChannel"]={"pos": 3240,"type":"int16"} #; % 3240
SH_def["SweepTaperlengthStart"]={"pos": 3242,"type":"int16"} #; % 3242
SH_def["SweepTaperLengthEnd"]={"pos": 3244,"type":"int16"} #; % 3244
SH_def["TaperType"]={"pos": 3246,"type":"int16"} #; % 3246
SH_def["CorrelatedDataTraces"]={"pos": 3248,"type":"int16"} #; % 3248
SH_def["BinaryGain"]={"pos": 3250,"type":"int16"} #; % 3250
SH_def["AmplitudeRecoveryMethod"]={"pos": 3252,"type":"int16"} #; % 3252
SH_def["MeasurementSystem"]={"pos": 3254,"type":"int16"} #; % 3254
SH_def["ImpulseSignalPolarity"]={"pos": 3256,"type":"int16"} #; % 3256
SH_def["VibratoryPolarityCode"]={"pos": 3258,"type":"int16"} #; % 3258
SH_def["Unassigned1"]={"pos": 3260,"type":"int16", "n":120} # % 3260
SH_def["SegyFormatRevisionNumber"]={"pos": 3500,"type":"uint16"} #; % 3500
SH_def["FixedLengthTraceFlag"]={"pos": 3502,"type":"uint16"} #; % 3502
SH_def["NumberOfExtTextualHeaders"]={"pos": 3504,"type":"uint16"} #; % 3504
#% 3506-3600 UNASSIGNED (as 47*2byte integer = 94 byte)
SH_def["Unassigned2"]={"pos": 3506,"type":"int16", "n":47} # =fread(segyid,47,'int16'); % 3506
##############
# Initialize SEGY TRACE HEADER SPECIFICATION
@@ -310,15 +335,30 @@ def getSegyTraceHeader(SH,THN='cdp',data='none'):
pos=THpos+3600+(SH["ns"]*4+240)*(itrace-1);
txt="Reading trace header ",itrace," of ",ntraces,pos
txt="Reading trace header " + str(itrace) + " of " + str(ntraces) + " " +str(pos)
printverbose(txt,10);
thv[itrace-1],index = getValue(data,pos,THformat,'>',1)
txt=THN,"=",thv[itrace-1]
printverbose(txt,5);
txt=THN + "=" + str(thv[itrace-1])
printverbose(txt,10);
return thv
def getAllSegyTraceHeaders(SH,data='none'):
SegyTraceHeaders = {'filename': SH["filename"]}
if (data=='none'):
data = open(SH["filename"]).read()
for key in STH_def.keys():
sth = getSegyTraceHeader(SH,key,data)
SegyTraceHeaders[key]=sth
txt = "getAllSegyTraceHeaders : " + key
printverbose(txt,2)
return SegyTraceHeaders
def readSegyFast(filename) :
"""
@@ -354,7 +394,8 @@ def readSegyFast(filename) :
index=3200;
nd=(filesize-3200)/4
SegyTraceHeader=[]
# SegyTraceHeaders=[]
SegyTraceHeaders = getAllSegyTraceHeaders(SH,data)
# READ ALL DATA EXCEPT FOR SEGY HEADER
Data1 = getValue(data,index,'float','>',nd)
@@ -367,7 +408,7 @@ def readSegyFast(filename) :
printverbose("readSegyFast : read data",2)
return Data,SH,SegyTraceHeader
return Data,SH,SegyTraceHeaders
def readSegy(filename):
@@ -410,13 +451,15 @@ def readSegy(filename):
printverbose("readSegy : read data",2)
SegyTraceHeaders = getAllSegyTraceHeaders(SH,data)
#if (segypy_verbose>2):
# imshow(Data)
# title('pymat test')
# grid(True)
# show()
return Data,SH,SegyTraceHeader
return Data,SH,SegyTraceHeaders
def getSegyTrace(SH,itrace):
"""
@@ -434,13 +477,37 @@ def getSegyTrace(SH,itrace):
SegyTraceData = getValue(data,index,'float','>',SH['ns'])
return SegyTraceHeader,SegyTraceData
def getSegyHeader(filename):
"""
SegyHeader=getSegyHeader(filename)
"""
data = open(filename).read()
SegyHeader = {'filename': filename}
for key in SH_def.keys():
pos=SH_def[key]["pos"]
format=SH_def[key]["type"]
SegyHeader[key],index = getValue(data,pos,format,'>');
txt = str(pos) + " " + str(format) + " Reading " + key +"="+str(SegyHeader[key])
printverbose(txt,10)
filesize=len(data)
ntraces = (filesize-3600)/(SegyHeader['ns']*4+240)
SegyHeader["ntraces"]=ntraces;
printverbose('getSegyHeader : succesfully read '+filename,1)
return SegyHeader
def getSegyHeader2(filename):
"""
SegyHeader=getSegyHeader(filename)
"""
data = open(filename).read()
printverbose('getSegyHeader : trying to read from '+filename,1)
# START INDEX IN FILE