SEG-Y via Xarray
Opening SEG-Y Data
SEGY Backend for reading Seismic SEGY files.
SgyBackendEntrypoint
Bases: BackendEntrypoint
open_dataset(filename_or_obj, dim_byte_fields, drop_variables=None, head_df=None, extra_byte_fields=None, segyio_kwargs=None)
Open a SEGY file with a native Xarray front end.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
filename_or_obj |
Union[str, PathLike]
|
The SEG-Y file/path. |
required |
dim_byte_fields |
Dict[str, int]
|
Dimension names and byte location pairs. This should at a minimum have the
keys |
required |
drop_variables |
Union[tuple[str], None]
|
Ignored |
None
|
head_df |
Union[DataFrame, None]
|
The DataFrame output from |
None
|
extra_byte_fields |
dict
|
Additional header information to load into the Dataset. Defaults to None. |
None
|
segyio_kwargs |
Union[dict, None]
|
Extra keyword arguments for segyio.open |
None
|
Returns:
Type | Description |
---|---|
Dataset
|
Lazy segy file Dataset |
Example
This backend is registered within Xarray and is accessed automatically when using the
xr.open_dataset
method for files with extensions of .segy
and .sgy
.
Ensure the byte locations are correct for your data.
# 3D data
ds3d = xr.open_dataset(
segyfile_path,
dim_byte_fields={'iline':189, 'xline':193},
extra_byte_fields={'cdp_x':181, 'cdp_y':185},
)
# 2D data
ds2d = xr.open_dataset(
segyfile_path,
dim_byte_fields={'cdp':22},
extra_byte_fields={'cdp_x':181, 'cdp_y':185},
)
Saving SEG-Y Data
SegyWriter
Handles the writing of SEG-Y files from compatible Datasets. Usually this
class would not be used and SEGY-SAK users can write SEG-Y file via the seisio
accessor.
Example
Writing data with the seisio
accessor.
ds.seisio.to_segy()
to_segy(ds, data_var='data', vert_dimension='samples', dead_trace_var=None, trace_header_map=None, **dim_kwargs)
Output xarray dataset to SEG-Y format.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
ds |
Dataset
|
The input dataset |
required |
data_var |
str
|
The Dataset variable name for the output volume. |
'data'
|
vert_dimension |
str
|
Data dimension to output as vertical trace, defaults to 'samples'. |
'samples'
|
dead_trace_var |
Union[str, None]
|
A variable in the Dataset which signifies dead traces. |
None
|
trace_header_map |
Dict[str, int]
|
Defaults to None. A dictionary of Dataset variables and byte locations. The variable will be written to the trace headers in the assigned byte location. By default CMP=23, cdp_x=181, cdp_y=185, iline=189, xline=193. |
None
|
dim_kwargs |
The dimension/byte location pairs to output dimensions to. The number of dim_kwargs should be equal to the number of dimensions on the output data_array. The sort order will be as per the order passed to the function. |
{}
|
write_text_header(text, line_numbers=True)
Write the text header for the file. The line length limit is 80 characters.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
text |
str
|
The text to write, new lines have newline character |
required |
line_numbers |
bool
|
Add line numbers to the output text header. |
True
|