"""
Functions to load sample data.
"""
from typing import Callable, NamedTuple
import pandas as pd
from pygmt.exceptions import GMTInvalidInput
from pygmt.io import load_dataarray
from pygmt.src import which
def _load_japan_quakes():
"""
Load a table of earthquakes around Japan as a pandas.DataFrame.
The data are from the NOAA NGDC database.
Returns
-------
data : pandas.DataFrame
The data table. The column names are "year", "month", "day",
"latitude", "longitude", "depth_km", and "magnitude" of the
earthquakes.
"""
fname = which("@tut_quakes.ngdc", download="c")
return pd.read_csv(
fname,
header=1,
delim_whitespace=True,
names=[
"year",
"month",
"day",
"latitude",
"longitude",
"depth_km",
"magnitude",
],
)
def _load_ocean_ridge_points():
"""
Load a table of ocean ridge points for the entire world as a
pandas.DataFrame.
Returns
-------
data : pandas.DataFrame
The data table. The column names are "longitude" and "latitude".
"""
fname = which("@ridge.txt", download="c")
return pd.read_csv(
fname,
delim_whitespace=True,
names=["longitude", "latitude"],
skiprows=1,
comment=">",
)
def _load_baja_california_bathymetry():
"""
Load a table of ship observations of bathymetry off Baja California as a
pandas.DataFrame.
Returns
-------
data : pandas.DataFrame
The data table. The column names are "longitude", "latitude",
and "bathymetry".
"""
fname = which("@tut_ship.xyz", download="c")
return pd.read_csv(
fname, sep="\t", header=None, names=["longitude", "latitude", "bathymetry"]
)
def _load_usgs_quakes():
"""
Load a table of global earthquakes from the USGS as a pandas.DataFrame.
Returns
-------
data : pandas.DataFrame
The data table. Use ``print(data.describe())`` to see the available
columns.
"""
fname = which("@usgs_quakes_22.txt", download="c")
return pd.read_csv(fname)
def _load_fractures_compilation():
"""
Load a table of fracture lengths and azimuths as hypothetically digitized
from geological maps as a pandas.DataFrame.
Returns
-------
data : pandas.DataFrame
The data table. The column names are "length" and
"azimuth" of the fractures.
"""
fname = which("@fractures_06.txt", download="c")
data = pd.read_csv(
fname, header=None, delim_whitespace=True, names=["azimuth", "length"]
)
return data[["length", "azimuth"]]
def _load_hotspots():
"""
Load a table with the locations, names, and suggested symbol sizes of
hotspots as a pandas.DataFrame.
The data are from Mueller, Royer, and Lawver, 1993, Geology, vol. 21,
pp. 275-278. The main 5 hotspots used by Doubrovine et al. [2012]
have symbol sizes twice the size of all other hotspots.
Returns
-------
data : pandas.DataFrame
The data table. The column names are "longitude", "latitude",
"symbol_size", and "place_name".
"""
fname = which("@hotspots.txt", download="c")
return pd.read_csv(
fname,
sep="\t",
skiprows=3,
names=["longitude", "latitude", "symbol_size", "place_name"],
)
def _load_mars_shape():
"""
Load a table of data for the shape of Mars as a pandas.DataFrame.
Data and information are from Smith, D. E., and M. T. Zuber (1996),
The shape of Mars and the topographic signature of the hemispheric
dichotomy.
Returns
-------
data : pandas.DataFrame
The data table with column names "longitude", "latitude", and
"radius_m".
"""
fname = which("@mars370d.txt", download="c")
data = pd.read_csv(
fname, sep="\t", header=None, names=["longitude", "latitude", "radius_m"]
)
return data
def _load_rock_sample_compositions():
"""
Loads a table of rock sample compositions.
Returns
-------
data : pandas.DataFrame
The data table with columns "limestone", "water", "air",
and "permittivity".
"""
fname = which("@ternary.txt", download="c")
return pd.read_csv(
fname,
delim_whitespace=True,
header=None,
names=["limestone", "water", "air", "permittivity"],
)
def _load_notre_dame_topography():
"""
Load Table 5.11 in Davis: Statistics and Data Analysis in Geology.
Returns
-------
data : pandas.DataFrame
The data table with columns "x", "y", and "z".
"""
fname = which("@Table_5_11.txt", download="c")
return pd.read_csv(fname, delim_whitespace=True, header=None, names=["x", "y", "z"])
def _load_maunaloa_co2():
"""
Load a table of CO2 values from Mauna Loa.
Returns
-------
data : pandas.DataFrame
The data table with columns "date" and "co2_ppm".
"""
fname = which("@MaunaLoa_CO2.txt", download="c")
return pd.read_csv(
fname, header=None, skiprows=1, delim_whitespace=True, names=["date", "co2_ppm"]
)
def _load_earth_relief_holes():
"""
Loads the remote file @earth_relief_20m_holes.grd.
Returns
-------
grid : :class:`xarray.DataArray`
The Earth relief grid. Coordinates are latitude and longitude in
degrees. Relief is in meters.
"""
fname = which("@earth_relief_20m_holes.grd", download="c")
return load_dataarray(fname, engine="netcdf4")
class GMTSampleData(NamedTuple):
"""
Information of a sample dataset.
Attributes
----------
func : callable
The function that loads the sample dataset.
description : str
The description of the sample dataset.
"""
func: Callable
description: str
datasets = {
"bathymetry": GMTSampleData(
func=_load_baja_california_bathymetry,
description="Table of ship bathymetric observations off Baja California",
),
"earth_relief_holes": GMTSampleData(
func=_load_earth_relief_holes,
description="Regional 20 arc-minutes Earth relief grid with holes",
),
"fractures": GMTSampleData(
func=_load_fractures_compilation,
description="Table of hypothetical fracture lengths and azimuths",
),
"hotspots": GMTSampleData(
func=_load_hotspots,
description="Table of locations, names, and symbol sizes of hotpots from "
"Müller et al. (1993)",
),
"japan_quakes": GMTSampleData(
func=_load_japan_quakes,
description="Table of earthquakes around Japan from the NOAA NGDC database",
),
"mars_shape": GMTSampleData(
func=_load_mars_shape,
description="Table of topographic signature of the hemispheric dichotomy of "
"Mars from Smith and Zuber (1996)",
),
"maunaloa_co2": GMTSampleData(
func=_load_maunaloa_co2,
description="Table of CO2 readings from Mauna Loa",
),
"notre_dame_topography": GMTSampleData(
func=_load_notre_dame_topography,
description="Table 5.11 in Davis: Statistics and Data Analysis in Geology",
),
"ocean_ridge_points": GMTSampleData(
func=_load_ocean_ridge_points,
description="Table of ocean ridge points for the entire world",
),
"rock_compositions": GMTSampleData(
func=_load_rock_sample_compositions,
description="Table of rock sample compositions",
),
"usgs_quakes": GMTSampleData(
func=_load_usgs_quakes,
description="Table of earthquakes from the USGS",
),
}
[docs]def list_sample_data():
"""
Report datasets available for tests and documentation examples.
Returns
-------
dict
Names and short descriptions of available sample datasets.
See Also
--------
load_sample_data : Load an example dataset from the GMT server.
"""
return {name: dataset.description for name, dataset in datasets.items()}
[docs]def load_sample_data(name):
# pylint: disable=line-too-long
"""
Load an example dataset from the GMT server.
The data are downloaded to a cache directory (usually ``~/.gmt/cache``) the
first time you invoke this function. Afterwards, it will load the data from
the cache. So you'll need an internet connection the first time around.
Parameters
----------
name : str
Name of the dataset to load.
Returns
-------
:class:`pandas.DataFrame` or :class:`xarray.DataArray`
Sample dataset loaded as a :class:`pandas.DataFrame` for tabular data or
:class:`xarray.DataArray` for raster data.
See Also
--------
list_sample_data : Report datasets available for tests and documentation
examples.
Examples
--------
>>> from pprint import pprint
>>> from pygmt.datasets import list_sample_data, load_sample_data
>>> # use list_sample_data to see the available datasets
>>> pprint(list_sample_data(), width=120) # noqa: W505
{'bathymetry': 'Table of ship bathymetric observations off Baja California',
'earth_relief_holes': 'Regional 20 arc-minutes Earth relief grid with holes',
'fractures': 'Table of hypothetical fracture lengths and azimuths',
'hotspots': 'Table of locations, names, and symbol sizes of hotpots from Müller et al. (1993)',
'japan_quakes': 'Table of earthquakes around Japan from the NOAA NGDC database',
'mars_shape': 'Table of topographic signature of the hemispheric dichotomy of Mars from Smith and Zuber (1996)',
'maunaloa_co2': 'Table of CO2 readings from Mauna Loa',
'notre_dame_topography': 'Table 5.11 in Davis: Statistics and Data Analysis in Geology',
'ocean_ridge_points': 'Table of ocean ridge points for the entire world',
'rock_compositions': 'Table of rock sample compositions',
'usgs_quakes': 'Table of earthquakes from the USGS'}
>>> # load the sample bathymetry dataset
>>> data = load_sample_data("bathymetry")
"""
if name not in datasets:
raise GMTInvalidInput(f"Invalid dataset name '{name}'.")
return datasets[name].func()