Depreciated Writing SEG-Y

Warning

These methods have been depreciated in favour of an Xarray accessor method. Examples in this documentation have been updated to use the new method or consult the accessor reference.

`segy_writer(seisnc, segyfile, trace_header_map=None, il_chunks=None, dimension=None, silent=False, use_text=False)`

Convert siesnc format (NetCDF4) to SEGY.

Parameters:

Name	Type	Description	Default
`seisnc`	`(Dataset, string)`	The input SEISNC file either a path or the in memory xarray.Dataset	required
`segyfile`	`string`	The output SEG-Y file	required
`trace_header_map`	`dict`	Defaults to None. A dictionary of seisnc 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`
`il_chunks`	`int`	The size of data to work on - if you have memory limitations. Defaults to 10. This is primarily used for large 3D and ignored for 2D data.	`None`
`dimension`	`str`	Data dimension to output, defaults to 'twt' or 'depth' whichever is present	`None`
`silent`	`bool`	Turn off progress reporting. Defaults to False.	`False`
`use_text`	`bool`	Use the seisnc text for the EBCIDC output. This text usally comes from the loaded SEG-Y file and may not match the segysak SEG-Y output. Defaults to False and writes the default segysak EBCIDC	`False`

Source code in segysak/segy/_segy_writer.py

Python
def segy_writer(
    seisnc,
    segyfile,
    trace_header_map=None,
    il_chunks=None,
    dimension=None,
    silent=False,
    use_text=False,
):
    """Convert siesnc format (NetCDF4) to SEGY.

    Args:
        seisnc (xarray.Dataset, string): The input SEISNC file either a path or the in memory xarray.Dataset
        segyfile (string): The output SEG-Y file
        trace_header_map (dict, optional): Defaults to None. A dictionary of seisnc 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.
        il_chunks (int, optional): The size of data to work on - if you have memory
            limitations. Defaults to 10. This is primarily used for large 3D and ignored for 2D data.
        dimension (str): Data dimension to output, defaults to 'twt' or 'depth' whichever is present
        silent (bool, optional): Turn off progress reporting. Defaults to False.
        use_text (bool, optional): Use the seisnc text for the EBCIDC output. This text usally comes from
            the loaded SEG-Y file and may not match the segysak SEG-Y output. Defaults to False and writes
            the default segysak EBCIDC
    """
    warn(
        "segy_writer will be removed in v0.6, please use the accessor ds.seisio.to_segy() method instead.",
        DeprecationWarning,
        stacklevel=2,
    )
    if trace_header_map:
        check_tracefield(trace_header_map.values())

    if isinstance(seisnc, xr.Dataset):
        _segy_writer_input_handler(
            seisnc, segyfile, trace_header_map, dimension, silent, None, use_text
        )
    else:
        ncfile = seisnc
        if isinstance(il_chunks, int):
            chunking = {"iline": il_chunks}
        else:
            chunking = None
        with open_seisnc(ncfile, chunks=chunking) as seisnc:
            _segy_writer_input_handler(
                seisnc,
                segyfile,
                trace_header_map,
                dimension,
                silent,
                il_chunks,
                use_text,
            )

`segy_freewriter(seisnc, segyfile, data_array='data', trace_header_map=None, use_text=False, dead_trace_key=None, vert_dimension='twt', chunk_spec=None, silent=False, **dim_kwargs)`

Convert siesnc format (NetCDF4) to SEG-Y.

Parameters:

Name	Type	Description	Default
`seisnc`	`(Dataset, string)`	The input SEISNC file either a path or the in memory xarray.Dataset	required
`segyfile`	`string`	The output SEG-Y file	required
`data_array`	`string`	The Dataset variable name for the output volume.	`'data'`
`trace_header_map`	`dict`	Defaults to None. A dictionary of seisnc 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`
`use_text`	`book`	Use the seisnc text for the EBCIDC output. This text usally comes from the loaded SEG-Y file and may not match the segysak SEG-Y output. Defaults to False and writes the default segysak EBCIDC	`False`
`dead_trace_key`	`str`	The key for the Dataset variable to use for trace output filter.	`None`
`vert_dimension`	`str`	Data dimension to output, defaults to 'twt' or 'depth' whichever is present.	`'twt'`
`chunk_spec`	`dict`	Xarray open_dataset chunking spec.	`None`
`silent`	`bool`	Turn off progress reporting. Defaults to False.	`False`
`dim_kwargs`	`int`	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.	`{}`

Source code in segysak/segy/_segy_freewriter.py

Python
def segy_freewriter(
    seisnc,
    segyfile,
    data_array="data",
    trace_header_map=None,
    use_text=False,
    dead_trace_key=None,
    vert_dimension="twt",
    chunk_spec=None,
    silent=False,
    **dim_kwargs,
):
    """Convert siesnc format (NetCDF4) to SEG-Y.

    Args:
        seisnc (xarray.Dataset, string): The input SEISNC file either a path or the in memory xarray.Dataset
        segyfile (string): The output SEG-Y file
        data_array (string): The Dataset variable name for the output volume.
        trace_header_map (dict, optional): Defaults to None. A dictionary of seisnc 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.
        use_text (book, optional): Use the seisnc text for the EBCIDC output. This text usally comes from
            the loaded SEG-Y file and may not match the segysak SEG-Y output. Defaults to False and writes
            the default segysak EBCIDC
        dead_trace_key (str): The key for the Dataset variable to use for trace output filter.
        vert_dimension (str): Data dimension to output, defaults to 'twt' or 'depth' whichever
            is present.
        chunk_spec (dict, optional): Xarray open_dataset chunking spec.
        silent (bool, optional): Turn off progress reporting. Defaults to False.
        dim_kwargs (int): 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.
    """
    warn(
        "segyfree_writer will be removed in v0.6, please use the accessor ds.seisio.to_segy method instead.",
        DeprecationWarning,
        stacklevel=2,
    )

    kwargs = dict(
        data_array=data_array,
        trace_header_map=trace_header_map,
        silent=silent,
        use_text=use_text,
        dead_trace_key=dead_trace_key,
        vert_dimension=vert_dimension,
    )

    if isinstance(seisnc, xr.Dataset):
        _segy_freewriter(
            seisnc,
            segyfile,
            **kwargs,
            **dim_kwargs,
        )
    else:
        ncfile = seisnc
        with open_seisnc(ncfile, chunks=chunk_spec) as seisnc:
            _segy_freewriter(
                seisnc,
                segyfile,
                **kwargs,
                **dim_kwargs,
            )

`output_byte_locs(name)`

Return common bytes position variable_dict for segy_writer.

Parameters:

Name	Type	Description	Default
`name`	`str`	One of [standard_3d, petrel_3d]	required

Returns:

Name	Type	Description
`dict`		A dictionary of SEG-Y byte positions and default seisnc variable pairs.

Example

segywriter(ncfile, 'segyfile.sgy', trace_header_map=output_byte_loc('petrel'))

Source code in segysak/segy/_segy_writer.py

Python
def output_byte_locs(name):
    """Return common bytes position variable_dict for segy_writer.

    Args:
        name (str): One of [standard_3d, petrel_3d]

    Returns:
        dict: A dictionary of SEG-Y byte positions and default seisnc variable
            pairs.

    Example:
        >>> segywriter(ncfile, 'segyfile.sgy', trace_header_map=output_byte_loc('petrel'))
        >>>
    """
    try:
        return OUTPUT_BYTES[name]
    except KeyError:
        raise ValueError(
            f"No byte locatons for {name}, select from {list(OUTPUT_BYTES.keys())}"
        )