xrspatial.multispectral.gci

xrspatial.multispectral.gci(nir_agg: xarray.core.dataarray.DataArray, green_agg: xarray.core.dataarray.DataArray, name='gci')[source]

Computes Green Chlorophyll Index. Used to estimate the content of leaf chorophyll and predict the physiological state of vegetation and plant health.

Parameters
  • nir_agg (xr.DataArray) – 2D array of near-infrared band data.

  • green_agg (xr.DataArray) – 2D array of green band data.

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

Returns

gci_agg – 2D array of gci values. All other input attributes are preserved.

Return type

xarray.DataArray of the same type as inputs

References

Examples

import matplotlib.pyplot as plt
from xrspatial.multispectral import gci
from xrspatial.datasets import get_data

# Open Example Data
data = get_data('sentinel-2')

nir = data['NIR']
green = data['Green']

# Generate GCI Aggregate Array
gci_agg = gci(nir_agg = nir,
              green_agg = green)

# Plot NIR Band
nir.plot(cmap = 'Greys', aspect = 2, size = 4)
plt.title("NIR Band")
plt.ylabel("latitude")
plt.xlabel("longitude")

# Plot Green Band
green.plot(cmap = 'Greys', aspect = 2, size = 4)
plt.title("Green Band")
plt.ylabel("latitude")
plt.xlabel("longitude")

# Plot GCI
gci_agg.plot(cmap = 'Greys', aspect = 2, size = 4)
plt.title("GCI")
plt.ylabel("latitude")
plt.xlabel("longitude")
../../_images/xrspatial-multispectral-gci-1_00.png

(png, hires.png, pdf)

../../_images/xrspatial-multispectral-gci-1_01.png

(png, hires.png, pdf)

../../_images/xrspatial-multispectral-gci-1_02.png

(png, hires.png, pdf)

>>> print(gci_agg[100:103, 100: 102])
<xarray.DataArray 'gci' (y: 3, x: 2)>
array([[0.35625   , 0.33097345],
       [0.3420342 , 0.29551451],
       [0.34822242, 0.28270413]])
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