rast-hist

#!/usr/bin/env python3
# Author: Daniel Rode
# Created: 01 Nov 2024
# Updated: -


import sys
from sys import exit
import rasterio
import numpy as np
import seaborn as sns


DPI = 300
BINS = 100
YLOG = False
TITLE = "Frequency Histogram"
HELP_TEXT = "Usage: this.py  SRC_RAST  OUT_PLOT_PNG"


# Parse command line arguments
pos_args = []
args = iter(sys.argv[1:])
for a in args:
  if not a.startswith('-'):
    pos_args.append(a)
    continue
  match a:
    case '-y' | '--y-axis-log-scale':
      YLOG = True
    case '-b' | '--bins':
      BINS = int(next(args))
    case '-d' | '--dpi':
      DPI = int(next(args))
    case '-t' | '--title':
      TITLE = next(args)
    case _:
      print("error: Invalid flag", a)
      exit(1)
try:
  IN_PATH, OUT_PATH = pos_args
except ValueError:
  print(HELP_TEXT)
  exit(1)


# Get values to plot from raster
with rasterio.open(IN_PATH, "r") as f:
    nums = f.read()
nums = nums[0]  # Choose first layer
nums = nums[~np.isnan(nums)]  # Drop NA

# Plot and save histograms
plt = sns.histplot(data=nums, bins=BINS, legend=False)
plt.set_title(TITLE)
if YLOG:
  plt.axes.set_yscale('log')
plt.get_figure().savefig(OUT_PATH, bbox_inches='tight', dpi=DPI)