xrspatial.viewshed.viewshed#
- xrspatial.viewshed.viewshed(raster: xarray.core.dataarray.DataArray, x: Union[int, float], y: Union[int, float], observer_elev: float = 0, target_elev: float = 0) xarray.core.dataarray.DataArray[source]#
Calculate viewshed of a raster (the visible cells in the raster) for the given viewpoint (observer) location.
- Parameters
raster (xr.DataArray) – Input raster image.
x (int, float) – x-coordinate in data space of observer location.
y (int, float) – y-coordinate in data space of observer location.
observer_elev (float) – Observer elevation above the terrain.
target_elev (float) – Target elevation offset above the terrain.
- Returns
viewshed – A cell x in the visibility grid is recorded as follows: If it is invisible, then x is set to INVISIBLE. If it is visible, then x is set to the vertical angle w.r.t the viewpoint.
- Return type
xarray.DataArray
Examples
>>> import numpy as np >>> import xarray as xr >>> from xrspatial import viewshed >>> data = np.array([ ... [0, 0, 1, 0, 0], ... [1, 3, 0, 0, 0], ... [10, 2, 5, 2, -1], ... [11, 1, 2, 9, 0]]) >>> terrain = xr.DataArray(data, dims=['y', 'x']) >>> h, w = data.shape >>> terrain['y'] = np.linspace(1, h, h) >>> terrain['x'] = np.linspace(1, w, w) >>> terrain <xarray.DataArray (y: 4, x: 5)> array([[ 0, 0, 1, 0, 0], [ 1, 3, 0, 0, 0], [10, 2, 5, 2, -1], [11, 1, 2, 9, 0]]) Coordinates: * y (y) float64 1.0 2.0 3.0 4.0 * x (x) float64 1.0 2.0 3.0 4.0 5.0 >>> viewshed(terrain, x=3, y=2) <xarray.DataArray (y: 4, x: 5)> array([[ -1. , 90. , 135. , 90. , -1.], [ -1. , 161.56505118, 180. , 90. , 90.], [167.39561735, 144.73561032, 168.69006753, 144.73561032, -1.], [165.57993189, -1. , -1. , 166.0472636 , -1.]]) Coordinates: * x (x) float64 1.0 2.0 3.0 4.0 5.0 * y (y) float64 1.0 2.0 3.0 4.0