HealPIX Image visualization

HealPIX maps can be viewed as a 2D image rotated by 45 deg. This is useful for quick visualization with image viewers without distorting the native pixels of the image.

import matplotlib.pyplot as plt
import numpy as np
import torch

from matplotlib.colors import Normalize
from PIL import Image

from earth2grid.healpix import Grid

grid = Grid(level=8)
lat = torch.tensor(grid.lat)
lat_img = grid.to_image(lat)

# Use Image to save at full resolution
normalizer = Normalize(vmin=np.nanmin(lat_img), vmax=np.nanmax(lat_img))
array = normalizer(lat_img)
array = plt.cm.viridis(array)
array = (256 * array).astype("uint8")
# set transparency for nans
array[..., -1] = np.where(np.isnan(lat_img), 0, 255)
image = Image.fromarray(array)
image.save("hpx_grid.png")

Warning, cannot find healpixpad module