Depreciated Xarray Accessor modules
Warning
These methods have been depreciated in favour of a new segysak
Xarray accessor.
Examples in this documentation have been updated to use the new accessor or consult the
reference.
Accessor modules are accessed as namespaces within the Xarray.Dataset objects
created by SEGY-SAK. When segysak
is imported, all xarray.Dataset
objects will
contain the .seis
and .seisio
namespaces.
segysak Xarray accessor modules
SeisIO
to_netcdf(file_path, **kwargs)
Output to netcdf4 with specs for seisnc.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
file_path |
Union[str, PathLike]
|
The output file path. |
required |
**kwargs |
Dict[str, Any]
|
As per xarray function to_netcdf. |
{}
|
to_segy(segy_file, use_text=True, coord_scalar=None, data_var='data', vert_dimension='samples', write_dead_traces=False, dead_trace_var=None, trace_header_map=None, **dim_kwargs)
Output Xarray Dataset to SEG-Y format.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
segy_file |
Union[str, PathLike]
|
The output file to write to. |
required |
use_text |
bool
|
Write the |
True
|
coord_scalar |
Union[float, None]
|
A SEG-Y compatible coordinate scalar. |
None
|
data_var |
str
|
The variable name of the trace data in the Dataset. |
'data'
|
vert_dimension |
str
|
The vertical (samples) dimension of the data_var. |
'samples'
|
write_dead_traces |
bool
|
Write dead traces as zeros to the SEG-Y file. |
False
|
dead_trace_var |
Union[str, None]
|
A dataset variable containing boolean values that identifies dead traces on the non-vertical dimension. |
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 |
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 trace sort order will be as per the order passed to the function. |
{}
|
Example
ds3d.seisio.to_segy(
"output_file.segy",
use_text = True,
vert_dimension = "samples",
trace_header_map = {'cdp_x':181, 'cdp_y':185}
iline = 189,
xline = 193,
)
to_subsurface()
Convert seismic data to a subsurface StructuredData Object
Raises:
Type | Description |
---|---|
err
|
[description] |
NotImplementedError
|
[description] |
Returns:
Type | Description |
---|---|
subsurface.structs.base_structures.StructuredData: subsurface struct |
SeisGeom
Bases: TemplateAccessor
calc_corner_points()
Calculate the corner points of the geometry or end points of a 2D line.
This puts two properties in the seisnc attrs with the calculated il/xl and cdp_x and cdp_y if available.
Attr
ds.attrs['corner_points'] ds.attrs['corner_points_xy']
fill_cdpna()
Fills NaN cdp locations by fitting known cdp x and y values to the local grid using a planar surface relationshipt.
get_affine_transform()
Calculate the forward iline/xline -> cdp_x, cdp_y Affine transform for Matplotlib using corner point geometry.
Returns:
Type | Description |
---|---|
matplotlib.transforms.Affine2D: |
Raises:
Type | Description |
---|---|
ValueError
|
If Dataset is not 3D |
get_dead_trace_map(scan=None, zeros_as_nan=False)
Scan the vertical axis of a volume to find traces that are all NaN and return an DataArray which maps the all dead traces.
Faster scans can be performed by setting scan to an int or list of int representing horizontal slice indexes to use for the scan.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
scan |
int/list of int
|
Horizontal indexes to scan. Defaults to None (scan full volume). |
None
|
zeros_as_nan |
bool
|
Treat zeros as NaN during scan. |
False
|
Returns:
Type | Description |
---|---|
xarray.DataArray: boolean dead trace map. |
get_measurement_system()
Return measurement_system if present, else None
grid_rotation()
Calculate the rotation of the grid using the sum under the curve method.
(x2 − x1)(y2 + y1)
Returns a value >0 if the rotation of points along inline is clockwise.
interp_line(cdp_x, cdp_y, extra=None, bin_spacing_hint=10, line_method='slinear', xysel_method='linear')
Select data at x and y coordinates
Parameters:
Name | Type | Description | Default |
---|---|---|---|
bin_spacing_hint |
number
|
a bin spacing to stay close to, in cdp world units. Default: 10 |
10
|
line_method |
string
|
valid values for the kind argument in scipy.interpolate.interp1d |
'slinear'
|
xysel_method |
string
|
valid values for DataArray.interp |
'linear'
|
Returns:
Type | Description |
---|---|
xarray.Dataset: Interpolated traces along the arbitrary line |
is_2d()
Returns True if the dataset is 2D peformant else False
is_2dgath()
Returns True if the dataset is 2D peformant and has offset or angle else False
is_3d()
Returns True if the dataset is 3D peformant else False
is_3dgath()
Returns True if the dataset is 3D peformant and has offset or angle else False
is_depth()
Check if seisnc volume is in depth
is_empty()
Check if empty
is_twt()
Check if seisnc volume is in twt
plot_bounds(ax=None)
Plot survey bbounding box to a new or existing axis
Parameters:
Name | Type | Description | Default |
---|---|---|---|
ax |
(optional) axis to plot to |
None
|
Returns:
Type | Description |
---|---|
matplotlib axis used |
subsample_dims(**dim_kwargs)
Return a dictionary of subsampled dims suitable for xarray.interp.
This tool halves
Parameters:
Name | Type | Description | Default |
---|---|---|---|
dim_kwargs |
dimension names as keyword arguments with values of how many times we should divide the dimension by 2. |
{}
|
surface_from_points(points, attr, left=('cdp_x', 'cdp_y'), right=None, key=None, method='linear')
Sample a 2D point set with an attribute (like Z) to the seisnc geometry using interpolation.
Parameters:
Name | Type | Description | Default |
---|---|---|---|
points |
array - like
|
Nx2 array-like of points with coordinates corresponding to coord1 and coord2. |
required |
attr |
(array - like, str)
|
If str points should be a DataFrame where attr is the column name of the attribute to be interpolated to the seisnc geometry. Else attr is a 1D array of length N. |
required |
left |
tuple
|
Length 2 tuple of coordinate dimensions to interpolate to. |
('cdp_x', 'cdp_y')
|
right |
tuple
|
If points is DataFrame right is a length 2 tuple of column keys corresponding to coordinates in argument left. |
None
|
method |
str
|
The interpolation method to use for griddata from scipy. Defaults to 'linear' |
'linear'
|
Returns:
Type | Description |
---|---|
xr.Dataset: Surface with geometry specified in left. |
xysel(cdp_x, cdp_y, method='nearest', sample_dim_name='cdp')
Select data at x and y coordinates
Parameters:
Name | Type | Description | Default |
---|---|---|---|
method |
str
|
Same as methods for xarray.Dataset.interp |
'nearest'
|
sample_dim_name |
str
|
The name to give the output sampling dimension. |
'cdp'
|
Returns:
Type | Description |
---|---|
xarray.Dataset: At selected coordinates. |
zeros_like()
Create a new dataset with the same attributes and coordinates and dimensions but with data filled by zeros.