pygmt.datasets.load_earth_relief
- pygmt.datasets.load_earth_relief(resolution='01d', region=None, registration=None, data_source='igpp', use_srtm=False)[source]
Load the Earth relief datasets (topography and bathymetry) in various resolutions.
The grids are downloaded to a user data directory (usually
~/.gmt/server/earth/earth_relief
,~/.gmt/server/earth/earth_gebco
,~/.gmt/server/earth/earth_gebcosi
, or~/.gmt/server/earth/earth_synbath
) the first time you invoke this function. Afterwards, it will load the grid from the data directory. So you’ll need an internet connection the first time around.This module downloads the grids that can also be accessed by passing in the file name @earth_relief_type_res[_reg] to any grid processing function or plotting method. earth_relief_type is the GMT name for the dataset. The available options are earth_relief, earth_gebco, earth_gebcosi, and earth_synbath. res is the grid resolution (see below), and reg is the grid registration type (p for pixel registration or g for gridline registration).
The default color palette table (CPT) for this dataset is geo. It’s implicitly used when passing in the file name of the dataset to any grid plotting method if no CPT is explicitly specified. When the dataset is loaded and plotted as an
xarray.DataArray
object, the default CPT is ignored, and GMT’s default CPT (turbo) is used. To use the dataset-specific CPT, you need to explicitly setcmap="geo"
.Refer to https://www.generic-mapping-tools.org/remote-datasets/earth-relief.html for more details about available datasets, including version information and references.
- Parameters:
resolution (
Literal
['01d'
,'30m'
,'20m'
,'15m'
,'10m'
,'06m'
,'05m'
,'04m'
,'03m'
,'02m'
,'01m'
,'30s'
,'15s'
,'03s'
,'01s'
], default:'01d'
) – The grid resolution. The suffixd
,m
ands
stand for arc-degrees, arc-minutes, and arc-seconds.region (
Sequence
[float
] |str
|None
, default:None
) – The subregion of the grid to load, in the form of a sequence [xmin, xmax, ymin, ymax] or an ISO country code. Required for grids with resolutions higher than 5 arc-minutes (i.e.,"05m"
).registration (
Literal
['gridline'
,'pixel'
,None
], default:None
) – Grid registration type. Either"pixel"
for pixel registration or"gridline"
for gridline registration. Default isNone
, means"gridline"
for all resolutions except"15s"
which is"pixel"
only.data_source (
Literal
['igpp'
,'gebco'
,'gebcosi'
,'synbath'
], default:'igpp'
) –Select the source for the Earth relief data. Available options are:
"igpp"
: IGPP Earth Relief. See https://www.generic-mapping-tools.org/remote-datasets/earth-relief.html."synbath"
: IGPP Earth Relief dataset that uses stastical properties of young seafloor to provide a more realistic relief of young areas with small seamounts."gebco"
: GEBCO Earth Relief with only observed relief and inferred relief via altimetric gravity. See https://www.generic-mapping-tools.org/remote-datasets/earth-gebco.html."gebcosi"
: GEBCO Earth Relief that gives sub-ice (si) elevations.
use_srtm (
bool
, default:False
) – By default, the land-only SRTM tiles from NASA are used to generate the"03s"
and"01s"
grids, and the missing ocean values are filled by up-sampling the SRTM15 tiles which have a resolution of 15 arc-seconds (i.e.,"15s"
). If True, will only load the original land-only SRTM tiles. Only works whendata_source="igpp"
.
- Return type:
- Returns:
grid – The Earth relief grid. Coordinates are latitude and longitude in degrees. Relief is in meters.
Note
The registration and coordinate system type of the returned
xarray.DataArray
grid can be accessed via the GMT accessors (i.e.,grid.gmt.registration
andgrid.gmt.gtype
respectively). However, these properties may be lost after specific grid operations (such as slicing) and will need to be manually set before passing the grid to any PyGMT data processing or plotting functions. Refer topygmt.GMTDataArrayAccessor
for detailed explanations and workarounds.Examples
>>> from pygmt.datasets import load_earth_relief >>> # load the default grid (gridline-registered 1 arc-degree grid) >>> grid = load_earth_relief() >>> # load the 30 arc-minutes grid with "gridline" registration >>> grid = load_earth_relief(resolution="30m", registration="gridline") >>> # load high-resolution (5 arc-minutes) grid for a specific region >>> grid = load_earth_relief( ... resolution="05m", ... region=[120, 160, 30, 60], ... registration="gridline", ... ) >>> # load the original 3 arc-seconds land-only SRTM tiles from NASA >>> grid = load_earth_relief( ... resolution="03s", ... region=[135, 136, 35, 36], ... registration="gridline", ... use_srtm=True, ... )
Examples using pygmt.datasets.load_earth_relief
Calculating grid gradient and radiance
Calculating grid gradient with custom azimuth and normalize parameters
Cross-section along a transect
Creating a 3-D perspective image
Creating a map with contour lines
Draping a dataset on top of a topographic surface
Interactive data visualization using Panel
Performing grid histogram equalization