"""
sphinterpolate - Spherical gridding in tension of data on a sphere
"""
from pygmt.clib import Session
from pygmt.helpers import (
GMTTempFile,
build_arg_string,
fmt_docstring,
kwargs_to_strings,
use_alias,
)
from pygmt.io import load_dataarray
__doctest_skip__ = ["sphinterpolate"]
[docs]
@fmt_docstring
@use_alias(
G="outgrid",
I="spacing",
R="region",
V="verbose",
)
@kwargs_to_strings(I="sequence", R="sequence")
def sphinterpolate(data, **kwargs):
r"""
Create spherical grid files in tension of data.
Reads a table containing *lon, lat, z* columns and performs a Delaunay
triangulation to set up a spherical interpolation in tension. Several
options may be used to affect the outcome, such as choosing local versus
global gradient estimation or optimize the tension selection to satisfy one
of four criteria.
Full option list at :gmt-docs:`sphinterpolate.html`
{aliases}
Parameters
----------
data : str, {table-like}
Pass in (x, y, z) or (longitude, latitude, elevation) values by
providing a file name to an ASCII data table, a 2-D
{table-classes}.
{outgrid}
{spacing}
{region}
{verbose}
Returns
-------
ret: xarray.DataArray or None
Return type depends on whether the ``outgrid`` parameter is set:
- :class:`xarray.DataArray` if ``outgrid`` is not set
- None if ``outgrid`` is set (grid output will be stored in file set by
``outgrid``)
Example
-------
>>> import pygmt
>>> # Load a table of Mars with longitude/latitude/radius columns
>>> mars_shape = pygmt.datasets.load_sample_data(name="mars_shape")
>>> # Perform Delaunay triangulation on the table data
>>> # to produce a grid with a 1 arc-degree spacing
>>> grid = pygmt.sphinterpolate(data=mars_shape, spacing=1, region="g")
"""
with GMTTempFile(suffix=".nc") as tmpfile:
with Session() as lib:
file_context = lib.virtualfile_from_data(check_kind="vector", data=data)
with file_context as infile:
if (outgrid := kwargs.get("G")) is None:
kwargs["G"] = outgrid = tmpfile.name # output to tmpfile
lib.call_module(
module="sphinterpolate",
args=build_arg_string(kwargs, infile=infile),
)
return load_dataarray(outgrid) if outgrid == tmpfile.name else None