Classification#

The classification tools let you reclassify the values in an xarray DataArray into a new set of values based on set bins.

Importing Packages#

[1]:
import numpy as np
import xarray as xr

import datashader as ds
from datashader.transfer_functions import shade
from datashader.transfer_functions import stack
from datashader.transfer_functions import dynspread
from datashader.transfer_functions import set_background
from datashader.colors import Elevation

import xrspatial

Generate Terrain Data#

To test out the classification functions, we’ll need some rasterized data. We can generate an artificial digital elevation model (dem), or terrain, with xarray-spatial’s generate_terrain, with the help of datashader’s Canvas for the aggregation of values into a raster.

[2]:
from xrspatial import generate_terrain
from xrspatial import hillshade

W = 800
H = 600

template_terrain = xr.DataArray(np.zeros((H, W)))
x_range = (-20e6, 20e6)
y_range = (-20e6, 20e6)

terrain = generate_terrain(
    template_terrain, x_range=x_range, y_range=y_range, seed=1, zfactor=1000
)
stack(
    shade(hillshade(terrain), cmap=["grey", "white"]),
    shade(terrain, cmap=Elevation, alpha=128),
)
/home/giancastro/miniconda3/envs/xrspatial/lib/python3.8/site-packages/numba/np/ufunc/parallel.py:365: NumbaWarning: The TBB threading layer requires TBB version 2019.5 or later i.e., TBB_INTERFACE_VERSION >= 11005. Found TBB_INTERFACE_VERSION = 9107. The TBB threading layer is disabled.
  warnings.warn(problem)
[2]: