nd.visualize package

Quickly visualize datasets.

nd.visualize.colorize(labels, N=None, nan_vals=[], cmap='jet')[source]

Apply a color map to a map of integer labels.

  • labels (np.array, shape (M,N)) – The labeled image.

  • N (int, optional) – The number of colors to use (default: 10)


A colored image in BGR space, ready to be handled by OpenCV.

Return type

np.array, shape (M,N,3)

nd.visualize.plot_map(ds, buffer=None, background='_default', imscale=6, gridlines=True, coastlines=True, scalebar=True, gridlines_kwargs={})[source]

Show the boundary of the dataset on a visually appealing map.

  • ds (xr.Dataset or xr.DataArray) – The dataset whose bounds to plot on the map.

  • buffer (float, optional) – Margin around the bounds polygon to plot, relative to the polygon dimension. By default, add around 20% on each side.

  • background (cartopy.io.img_tiles image tiles, optional) – The basemap to plot in the background (default: Stamen terrain). If None, do not plot a background map.

  • imscale (int, optional) – The zoom level of the background image (default: 6).

  • gridlines (bool, optional) – Whether to plot gridlines (default: True).

  • coastlines (bool, optional) – Whether to plot coastlines (default: True).

  • scalebar (bool, optional) – Whether to add a scale bar (default: True).

  • gridlines_kwargs (dict, optional) – Additional keyword arguments for gridlines_with_labels().


The corresponding GeoAxes object.

Return type


nd.visualize.to_rgb(data, output=None, vmin=None, vmax=None, pmin=2, pmax=98, categorical=False, mask=None, shape=None, cmap=None)[source]

Turn some data into a numpy array representing an RGB image.

  • data (list of DataArray) –

  • output (str) – file path

  • vmin (float or list of float) – minimum value, or list of values per channel (default: None).

  • vmax (float or list of float) – maximum value, or list of values per channel (default: None).

  • pmin (float) – lowest percentile to plot (default: 2). Ignored if vmin is passed.

  • pmax (float) – highest percentile to plot (default: 98). Ignored if vmax is passed.

  • categorical (bool, optional) – Whether the data is categorical. If True, return a randomly colorized image according to the data value (default: False).

  • mask (np.ndarray, optional) – If specified, parts of the image outside of the mask will be black.

  • shape (tuple, optional) – The output height and width (either or both may be None)

  • cmap (opencv colormap, optional) – The colormap used to colorize grayscale data


Returns the generate RGB image if output is None, else returns None.

Return type

np.ndarray or None

nd.visualize.write_video(ds, path, timestamp='upper left', fontcolor=(0, 0, 0), width=None, height=None, fps=1, codec=None, rgb=<function <lambda>>, cmap=None, mask=None, **kwargs)[source]

Create a video from an xarray.Dataset.

  • ds (xarray.Dataset or xarray.DataArray) – The dataset must have dimensions ‘y’, ‘x’, and ‘time’.

  • path (str) – The output file path of the video.

  • timestamp (str, optional) – Location to print the timestamp: [‘upper left’, ‘lower left’, ‘upper right’, ‘lower right’, ‘ul’, ‘ll’, ‘ur’, ‘lr’] Set to None to disable (default: ‘upper left’).

  • fontcolor (tuple, optional) – RGB tuple for timestamp font color (default: (0, 0, 0), i.e., black).

  • width (int, optional) – The width of the video (default: ds.dim[‘x’])

  • height (int, optional) – The height of the video (default: ds.dim[‘y’])

  • fps (int, optional) – Frames per second (default: 1).

  • codec (str, optional) – fourcc codec (see http://www.fourcc.org/codecs.php)

  • rgb (callable, optional) – A callable that takes a Dataset as input and returns a list of R, G, B channels. By default will compute the C11, C22, C11/C22 representation. For a DataArray, use cmap.

  • cmap (str, optional) – For DataArrays only. Colormap used to colorize univariate data.

  • mask (np.ndarray, optional) – If specified, parts of the image outside of the mask will be black.