xrspatial.hillshade.hillshade#

xrspatial.hillshade.hillshade(agg: DataArray, azimuth: int = 225, angle_altitude: int = 25, name: str | None = 'hillshade', shadows: bool = False, boundary: str = 'nan') → DataArray[source]#

Calculates, for all cells in the array, an illumination value of each cell based on illumination from a specific azimuth and altitude.

Parameters:

  • agg (xarray.DataArray or xr.Dataset) – 2D NumPy, CuPy, NumPy-backed Dask, or Cupy-backed Dask array of elevation values. If a Dataset is passed, the operation is applied to each data variable independently.

  • angle_altitude (int, default=25) – Altitude angle of the sun specified in degrees.

  • azimuth (int, default=225) – The angle between the north vector and the perpendicular projection of the light source down onto the horizon specified in degrees.

  • name (str, default='hillshade') – Name of output DataArray.

  • shadows (bool, default=False) – Whether to calculate shadows or not. Shadows are available only for Cupy-backed Dask arrays and only if rtxpy is installed and appropriate graphics hardware is available.

  • boundary (str, default='nan') – How to handle edges where the kernel extends beyond the raster. 'nan' — fill missing neighbours with NaN (default). 'nearest' — repeat edge values. 'reflect' — mirror at boundary. 'wrap' — periodic / toroidal.

Returns:

hillshade_agg – If agg is a DataArray, returns a DataArray of the same type. If agg is a Dataset, returns a Dataset with hillshade computed for each data variable. 2D aggregate array of illumination values.

Return type:

xarray.DataArray or xr.Dataset

References

Examples

>>> import numpy as np
>>> import xarray as xr
>>> from xrspatial import hillshade
>>> data = np.array([
...    [0., 0., 0., 0., 0.],
...    [0., 1., 0., 2., 0.],
...    [0., 0., 3., 0., 0.],
...    [0., 0., 0., 0., 0.],
...    [0., 0., 0., 0., 0.]])
>>> n, m = data.shape
>>> raster = xr.DataArray(data, dims=['y', 'x'], name='raster')
>>> raster['y'] = np.arange(n)[::-1]
>>> raster['x'] = np.arange(m)
>>> hillshade_agg = hillshade(raster)