How to read latitude/longitude or xcoordinate/ycoordinate information??

[SoumiC]

Hi,
I need to know how to read latitude/longitude or xcoordinate/ycoordinate information from a .sgy file instead of inline/xline? I need to know the field names for extraction.

Thank you.
Regards,
Soumi

[rob-smallshire]

for inline_xline in segy_reader.inline_xline_numbers():
    index = segy_reader.trace_index(inline_xline)
    header = segy_reader.trace_header(index)
    # Do something with the header e.g. print it to look at the field names and values
    # You'll need to identify which fields contain the coordinate you're looking for
    print(header)

[keerthigajee]

Hi,
I am trying to read x and y coordinates from seg file using given code but, it showing this error :
EOFError: Trace header truncated when reading from position 3600 with packer BijectiveHeaderPacker(TraceHeaderRev1), how to rectify this issue and I need to know the field names for trace header..

Thank you,
Regards,
keerthi.

[rob-smallshire]

@keerthigajee It's difficult to say what the problem is unless you can share your SEG-Y file in some way. You can see the header field names in the code here

segpy/segpy/trace_header.py

Line 257 in d39b89c

class TraceHeaderRev0(Header):

[adclose]

So I'm having the same issue I believe it may have something to do with the size of the trace header.

I get this when I simply try to see the header
"segydata.trace_header(0)
Traceback (most recent call last):
File "C:\Program Files\JetBrains\PyCharm Community Edition 2018.1.4\helpers\pydev_pydevd_bundle\pydevd_exec2.py", line 3, in Exec
exec(exp, global_vars, local_vars)
File "", line 1, in
File "C:\Users\Aaron\AppData\Local\Programs\Python\Python36\lib\site-packages\segpy\reader.py", line 514, in trace_header
trace_header = read_trace_header(self._fh, header_packer, pos)
File "C:\Users\Aaron\AppData\Local\Programs\Python\Python36\lib\site-packages\segpy\toolkit.py", line 457, in read_trace_header
"{} with packer {!r}".format(pos, trace_header_packer)) from e
EOFError: Trace header truncated when reading from position 3600 with packer BijectiveHeaderPacker(TraceHeaderRev1)"

Mine is in a 2D data file with what looks like non standard cdp_x and cdp_y bit locations but I'm not sure that is the issue.

Also is there a way to easily override the offset for those fields so that it will read the traces correctly?

[adclose]

After a lot of tracking down, I found an issue between the segy file I had and the format for the trace header, this may be related to the original problem and my not.

solution for me was to edit the trace_header.py to say

class Correlated(IntEnum):
"""Correlated: 0 = UNKNOWN,1 = no, 2 = yes."""
UNKNOWN = 0
NO = 1
YES = 2

Seems like sometimes segy files include 0 for this field

[InnoKaleid]

Hi,

I also run into the same issue: EOFError: Trace header truncated when reading from position 3600 with packer BijectiveHeaderPacker(TraceHeaderRev1).

I am trying to (1) read in a 2D seismic segy using create_reader [create_reader(segy_in_file, dimensionality=2)] and then (2) write it out into a new segy file using write_segy [write_segy(segy_out_file, seg_y_dataset, endian='>')]. The read-in step is fine while the error message occurs during the write-out step.

I zip the public segy file and attach it here.
3X_75_PR.zip. I was wondering if someone can help me with it?

Kindest regards,

John

[rob-smallshire]

I’m on vacation currently. I’ll take a look next week.

…

On Sat, 20 Apr 2019 at 18:19, InnoKaleid ***@***.***> wrote: Hi, I also run into the same issue: EOFError: Trace header truncated when reading from position 3600 with packer BijectiveHeaderPacker(TraceHeaderRev1). I am trying to (1) read in a 2D seismic segy using create_reader [create_reader(segy_in_file, dimensionality=2)] and then (2) write it out into a new segy file using write_segy [write_segy(segy_out_file, seg_y_dataset, endian='>')]. The read-in step is fine while the error message occurs during the write-out step. I zip the public segy file and attach it here. 3X_75_PR.zip <https://github.com/sixty-north/segpy/files/3100354/3X_75_PR.zip>. I was wondering if someone can help me with it? Kindest regards, John — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#90 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAH65KN46ACGTDRYRL6UWSTPRM7ADANCNFSM4GSK2U3A> .

[InnoKaleid]

Hi rob-smallshire,

Thank you and have a great vacation.

John

[adclose]

@InnoKaleid
This is my test code that should solve your problem
but you will need to need to replace the trace_header.py in the package with the attached

trace_header.zip

Best of Luck
Aaron

`
from segpy.reader import create_reader
import numpy as np

def getpoint(segydata, i, j = None):

if j is None:
    header = segydata.trace_header(segydata.trace_index(i))
else:
    header = segydata.trace_header(segydata.trace_index([i, j]))

if header.cdp_x != 0:
    x = header.cdp_x
    y = header.cdp_y
else:
    x = (header.source_x + header.group_x) / 2
    y = (header.source_y + header.group_y) / 2

point = np.array([x,y])

if (header.xy_scalar >= 0):
    scale = header.xy_scalar
else:
    scale = 1 / np.abs(header.xy_scalar)

point = point * scale

return point

filePath = "tmp/3X_75_PR.SGY"

fileHandle = open(filePath, 'rb')
segyData = create_reader(fileHandle)

imax = max(segyData.cdp_numbers())
imin = min(segyData.cdp_numbers())

for i in np.arange(imin, imax, 10):
point = getpoint(segyData, i)
if i == imin:
points = np.array([point])
else:
points = np.append(points, [point], axis=0)

print(points)

`

[InnoKaleid]

Hi Aaron,

Thank you for your help. It seems work well and have a great weekend.

John

[adclose]

John
No problem hope this helps..
I could have abstracted the answer a bit better but glad it works.. I’ve been using the library a lot this week so just pulled pieces of some of my working code.

[InnoKaleid]

Hi Aaron,

Thank you very much and your answer is very helpful. Happy Easter!

John

[pktrigg]

Hi, I too have the same error:
EOFError: Trace header truncated when reading from position 3600 with packer BijectiveHeaderPacker(TraceHeaderRev1)

any thoughts how this can be fixed in the pip distro module?

[adclose]

my fork should work for this.

Aaron

[satyajitchiku]

what is the use of progress in the reader and writer module and how to use it ????

[SoumiC]

Hello @rob-smallshire,
In case of 3D files, x-coordinates and y-coordinates fields are valid?
or these are valid only for 2D seismic files?

I tried to check the field names, but the EOFError issue persists.
"EOFError: Trace header truncated when reading from position 3600 with packer BijectiveHeaderPacker(TraceHeaderRev1)".

What to do with a 3D seismic file if x, y co-ordinates are required?

Kindly help!.

Regards,
Soumi

[adclose]

The EOF error is pretty common.
You might try my fork and see if that runs for you.
Aaron