"""
Non-plot GMT modules.
"""
import xarray as xr
from pygmt.clib import Session
from pygmt.exceptions import GMTInvalidInput
from pygmt.src.grdinfo import grdinfo
[docs]class config: # pylint: disable=invalid-name
"""
Set GMT defaults globally or locally.
Change GMT defaults globally::
pygmt.config(PARAMETER=value)
Change GMT defaults locally by using it as a context manager::
with pygmt.config(PARAMETER=value):
...
Full GMT defaults list at :gmt-docs:`gmt.conf.html`
"""
def __init__(self, **kwargs):
# Save values so that we can revert to their initial values
self.old_defaults = {}
self.special_params = {
"FONT": [
"FONT_ANNOT_PRIMARY",
"FONT_ANNOT_SECONDARY",
"FONT_HEADING",
"FONT_LABEL",
"FONT_TAG",
"FONT_TITLE",
],
"FONT_ANNOT": ["FONT_ANNOT_PRIMARY", "FONT_ANNOT_SECONDARY"],
"FORMAT_TIME_MAP": ["FORMAT_TIME_PRIMARY_MAP", "FORMAT_TIME_SECONDARY_MAP"],
"MAP_ANNOT_OFFSET": [
"MAP_ANNOT_OFFSET_PRIMARY",
"MAP_ANNOT_OFFSET_SECONDARY",
],
"MAP_GRID_CROSS_SIZE": [
"MAP_GRID_CROSS_SIZE_PRIMARY",
"MAP_GRID_CROSS_SIZE_SECONDARY",
],
"MAP_GRID_PEN": ["MAP_GRID_PEN_PRIMARY", "MAP_GRID_PEN_SECONDARY"],
"MAP_TICK_LENGTH": ["MAP_TICK_LENGTH_PRIMARY", "MAP_TICK_LENGTH_SECONDARY"],
"MAP_TICK_PEN": ["MAP_TICK_PEN_PRIMARY", "MAP_TICK_PEN_SECONDARY"],
}
with Session() as lib:
for key in kwargs:
if key in self.special_params:
for k in self.special_params[key]:
self.old_defaults[k] = lib.get_default(k)
else:
self.old_defaults[key] = lib.get_default(key)
# call gmt set to change GMT defaults
arg_str = " ".join(
["{}={}".format(key, value) for key, value in kwargs.items()]
)
with Session() as lib:
lib.call_module("set", arg_str)
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, traceback):
# revert to initial values
arg_str = " ".join(
["{}={}".format(key, value) for key, value in self.old_defaults.items()]
)
with Session() as lib:
lib.call_module("set", arg_str)
[docs]@xr.register_dataarray_accessor("gmt")
class GMTDataArrayAccessor:
"""
This is the GMT extension for :class:`xarray.DataArray`.
You can access various GMT specific metadata about your grid as follows:
>>> from pygmt.datasets import load_earth_relief
>>> # Use the global Earth relief grid with 1 degree spacing
>>> grid = load_earth_relief(resolution="01d")
>>> # See if grid uses Gridline (0) or Pixel (1) registration
>>> grid.gmt.registration
1
>>> # See if grid uses Cartesian (0) or Geographic (1) coordinate system
>>> grid.gmt.gtype
1
"""
def __init__(self, xarray_obj):
self._obj = xarray_obj
try:
self._source = self._obj.encoding["source"] # filepath to NetCDF source
# From the shortened summary information of `grdinfo`,
# get grid registration in column 10, and grid type in column 11
self._registration, self._gtype = map(
int, grdinfo(self._source, per_column="n", o="10,11").split()
)
except KeyError:
self._registration = 0 # Default to Gridline registration
self._gtype = 0 # Default to Cartesian grid type
@property
def registration(self):
"""
Registration type of the grid, either Gridline (0) or Pixel (1).
"""
return self._registration
@registration.setter
def registration(self, value):
if value in (0, 1):
self._registration = value
else:
raise GMTInvalidInput(
f"Invalid grid registration value: {value}, should be a boolean of "
"either 0 for Gridline registration or 1 for Pixel registration"
)
@property
def gtype(self):
"""
Coordinate system type of the grid, either Cartesian (0) or Geographic
(1).
"""
return self._gtype
@gtype.setter
def gtype(self, value):
if value in (0, 1):
self._gtype = value
else:
raise GMTInvalidInput(
f"Invalid coordinate system type: {value}, should be a boolean of "
"either 0 for Cartesian or 1 for Geographic"
)