xrspatial.multispectral.savi¶
- xrspatial.multispectral.savi(nir_agg: xarray.core.dataarray.DataArray, red_agg: xarray.core.dataarray.DataArray, soil_factor: float = 1.0, name: str = 'savi')[source]¶
Computes Soil Adjusted Vegetation Index (SAVI). Used to determine if a cell contains living vegetation while minimizing soil brightness.
- Parameters
nir_agg (xr.DataArray) – 2D array of near-infrared band data.
red_agg (xr.DataArray) – 2D array of red band data.
soil_factor (float, default=1.0) – soil adjustment factor between -1.0 and 1.0. When set to zero, savi will return the same as ndvi.
name (str, default='savi') – Name of output DataArray.
- Returns
savi_agg – 2D array of savi values. All other input attributes are preserved.
- Return type
xr.DataArray of same type as inputs
References
ScienceDirect: https://www.sciencedirect.com/science/article/abs/pii/003442578890106X # noqa
Examples
import matplotlib.pyplot as plt from xrspatial.multispectral import savi from xrspatial.datasets import get_data # Open Example Data data = get_data('sentinel-2') nir = data['NIR'] red = data['Red'] # Generate SAVI Aggregate Array savi_agg = savi(nir_agg = nir, red_agg = red) # Plot NIR Band nir.plot(cmap = 'Greys', aspect = 2, size = 4) plt.title("NIR Band") plt.ylabel("latitude") plt.xlabel("longitude") # Plot Red Band red.plot(cmap = 'Greys', aspect = 2, size = 4) plt.title("Red Band") plt.ylabel("latitude") plt.xlabel("longitude") # Plot SAVI savi_agg.plot(cmap = 'Greys', aspect = 2, size = 4) plt.title("SAVI") plt.ylabel("latitude") plt.xlabel("longitude")
>>> print(savi_agg[100:103, 100: 102]) <xarray.DataArray 'savi' (y: 3, x: 2)> array([[0.0337197 , 0.03087509], [0.0324884 , 0.02531194], [0.03353768, 0.02215077]]) Coordinates: * x (x) float64 6.01e+05 6.01e+05 * y (y) float64 4.699e+06 4.699e+06 4.699e+06 band int32 ... Attributes: (12/13) transform: [ 1.00000e+01 0.00000e+00 6.00000e+05 0.0000... # noqa crs: +init=epsg:32719 res: [10. 10.] is_tiled: 1 nodatavals: nan scales: 1.0 ... ... instrument: Sentinel-2 Band: 07 Name: NIR Bandwidth (µm): 115 Nominal Wavelength (µm): 0.842 Resolution (m): 10
