pygmt.datasets.load_blue_marble

pygmt.datasets.load_blue_marble(resolution='01d', region=None)

Load NASA Blue Marble images in various resolutions.

Earth day/night dataset.

The images are downloaded to a user data directory (usually ~/.gmt/server/earth/earth_day/) the first time you invoke this function. Afterwards, it will load the image from the data directory. So you’ll need an internet connection the first time around.

These images can also be accessed by passing in the file name @earth_day_res to any image processing function or plotting method. res is the image resolution (see below).

Refer to https://www.generic-mapping-tools.org/remote-datasets/earth-daynight.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'], default: '01d') – The image resolution. The suffix d, m, and s stand for arc-degrees, arc-minutes, and arc-seconds.

• region (Sequence[float] | str | None, default: None) – The subregion of the image to load, in the form of a sequence [xmin, xmax, ymin, ymax].

Return type:

DataArray

Returns:

image – The NASA Blue Marble image. Coordinates are latitude and longitude in degrees.

Note

The registration and coordinate system type of the returned xarray.DataArray image can be accessed via the GMT accessors (i.e., image.gmt.registration and image.gmt.gtype respectively). However, these properties may be lost after specific image operations (such as slicing) and will need to be manually set before passing the image to any PyGMT data processing or plotting functions. Refer to pygmt.GMTDataArrayAccessor for detailed explanations and workarounds.

Examples

>>> from pygmt.datasets import load_blue_marble
>>> # load the default image (pixel-registered 1 arc-degree image)
>>> image = load_blue_marble()