sfsegyread (4.2-git)
index
system/seismic/Msegyread.c
Documentation
Convert a SEG-Y or SU dataset to RSF.

 
Synopsis
        sfsegyread mask=msk.rsf > out.rsf tfile=hdr.rsf verb=n su= suxdr=n endian=y n2=0 format= ns=0 nsbyte=0 tape= hfile= bfile= read=

Data headers and trace headers are separated from the data.

"suread" is equivalent to "segyread su=y"


SEGY key names:

tracl: trace sequence number within line 0

tracr: trace sequence number within reel 4

fldr: field record number 8

tracf: trace number within field record 12

ep: energy source point number 16

cdp: CDP ensemble number 20

cdpt: trace number within CDP ensemble 24

trid: trace identification code:
1 = seismic data
2 = dead
3 = dummy
4 = time break
5 = uphole
6 = sweep
7 = timing
8 = water break
9---, N = optional use (N = 32,767) 28

nvs: number of vertically summed traces 30

nhs: number of horizontally summed traces 32

duse: data use:
1 = production
2 = test 34

offset: distance from source point to receiver
group (negative if opposite to direction
in which the line was shot) 36

gelev: receiver group elevation from sea level
(above sea level is positive) 40

selev: source elevation from sea level
(above sea level is positive) 44

sdepth: source depth (positive) 48

gdel: datum elevation at receiver group 52

sdel: datum elevation at source 56

swdep: water depth at source 60

gwdep: water depth at receiver group 64

scalel: scale factor for previous 7 entries
with value plus or minus 10 to the
power 0, 1, 2, 3, or 4 (if positive,
multiply, if negative divide) 68

scalco: scale factor for next 4 entries
with value plus or minus 10 to the
power 0, 1, 2, 3, or 4 (if positive,
multiply, if negative divide) 70

sx: X source coordinate 72

sy: Y source coordinate 76

gx: X group coordinate 80

gy: Y group coordinate 84

counit: coordinate units code:
for previous four entries
1 = length (meters or feet)
2 = seconds of arc (in this case, the
X values are unsigned longitude and the Y values
are latitude, a positive value designates
the number of seconds east of Greenwich
or north of the equator 88

wevel: weathering velocity 90

swevel: subweathering velocity 92

sut: uphole time at source 94

gut: uphole time at receiver group 96

sstat: source static correction 98

gstat: group static correction 100

tstat: total static applied 102

laga: lag time A, time in ms between end of 240-
byte trace identification header and time
break, positive if time break occurs after
end of header, time break is defined as
the initiation pulse which maybe recorded
on an auxiliary trace or as otherwise
specified by the recording system 104

lagb: lag time B, time in ms between the time
break and the initiation time of the energy source,
may be positive or negative 106

delrt: delay recording time, time in ms between
initiation time of energy source and time
when recording of data samples begins
(for deep water work if recording does not
start at zero time) 108

muts: mute time--start 110

mute: mute time--end 112

ns: number of samples in this trace 114

dt: sample interval, in micro-seconds 116

gain: gain type of field instruments code:
1 = fixed
2 = binary
3 = floating point
4 ---- N = optional use 118

igc: instrument gain constant 120

igi: instrument early or initial gain 122

corr: correlated:
1 = no
2 = yes 124

sfs: sweep frequency at start 126

sfe: sweep frequency at end 128

slen: sweep length in ms 130

styp: sweep type code:
1 = linear
2 = cos-squared
3 = other 132

stas: sweep trace length at start in ms 134

stae: sweep trace length at end in ms 136

tatyp: taper type: 1=linear, 2=cos^2, 3=other 138

afilf: alias filter frequency if used 140

afils: alias filter slope 142

nofilf: notch filter frequency if used 144

nofils: notch filter slope 146

lcf: low cut frequency if used 148

hcf: high cut frequncy if used 150

lcs: low cut slope 152

hcs: high cut slope 154

year: year data recorded 156

day: day of year 158

hour: hour of day (24 hour clock) 160

minute: minute of hour 162

sec: second of minute 164

timbas: time basis code:
1 = local
2 = GMT
3 = other 166

trwf: trace weighting factor, defined as 1/2^N
volts for the least sigificant bit 168

grnors: geophone group number of roll switch
position one 170

grnofr: geophone group number of trace one within
original field record 172

grnlof: geophone group number of last trace within
original field record 174

gaps: gap size (total number of groups dropped) 176

otrav: overtravel taper code:
1 = down (or behind)
2 = up (or ahead) 178

cdpx: X coordinate of CDP 180

cdpy: Y coordinate of CDP 184

iline: in-line number 188

xline: cross-line number 192

shnum: shotpoint number 196

shsca: shotpoint scalar 200

tval: trace value meas. 202

tconst4: transduction const 204

tconst2: transduction const 208

tunits: transduction units 210

device: device identifier 212

tscalar: time scalar 214

stype: source type 216

sendir: source energy dir. 218

unknown: unknown 222

smeas4: source measurement 224

smeas2: source measurement 228

smeasu: source measurement unit 230

unass1: unassigned 232

unass2: unassigned 236

additional keys can be created in the output trace headers
The parameters key1, key2, ... key# are used to additional keys.
The keys must be unique and different from the SEGY key names above.
The input header byte location and lengths must also be defined.
This capability is described in an example that defines a new keys
iline1 from byte 220 and xline1 from byte 224:
key1=iline1 iline1=220 key1_len=4 \
key2=xline1 xline1=224 key2_len=4 \

key#_len defaults to 4

 
Parameters
       
 
string bfile=
output binary data header file
 
bool endian=y [y/n]
Whether to automatically estimate endianness or not
 
int format= [1,2,3,5]
Data format.
The default is taken from binary header for segy input.
Default is 5 for su input.
1 is IBM floating point
2 is 4-byte integer
3 is 2-byte integer
5 is IEEE floating point
6 is native_float (same as RSF binary default)
7 is 1-byte integer

 
string hfile=
output text data header file
 
string mask=
optional header mask for reading only selected traces (auxiliary input file name)
 
int n2=0
number of traces to read (if 0, read all traces)
 
int ns=0
Number of samples. The default is taken from binary header
 
int nsbyte=0
byte number for ns in binary header
 
string read=
what to read: h - header, d - data, b - both (default)
 
bool su= [y/n]
y if input is SU, n if input is SEGY
 
bool suxdr=n [y/n]
y, SU has XDR support.
SU with xdr on (as downloaded), use endian=y suxdr=y
SU with xdr off in the makefiles, use endian=n suxdr=n

 
string tape=
input data
 
string tfile=
output trace header file (auxiliary output file name)
 
bool verb=n [y/n]
Verbosity flag

 
Used In
       

 
CWP
        geo2006TimeShiftImagingCondition/zicig
geo2007StereographicImagingCondition/sigsbee2
geo2008InterferometricImagingCondition/sact1
geo2008InterferometricImagingCondition/sigs2
geo2008IsotropicAngleDomainElasticRTM/marm2allA
geo2008IsotropicAngleDomainElasticRTM/marm2oneA
geo2008NumericWEMVAoperators/saltWEMVA
geo2009TTIModeSeparation/marmousi2
geo2009VTIModeSeparation/sigsbee
geo2011WideAzimuthAngleDecomposition/seam357
jse2006RWEImagingOverturningReflections/sigsbee
pept2011MicroearthquakeMonitoring/saf1
pept2011MicroearthquakeMonitoring/saf2
pept2011MicroearthquakeMonitoring/saf3

 
DATA
        alaska/foldplot
alaska/line31-81-m8r
boem-g3d1206-002a/displayin
bpmodel94/firstlook
bpstatics94/firstlook
bptti/data
bptti/modl
bptti2007/firstlook
bpvelanal2004/firstlook