Source code for polar2grid.add_colormap

#!/usr/bin/env python3
# encoding: utf-8
# Copyright (C) 2016-2022 Space Science and Engineering Center (SSEC),
# University of Wisconsin-Madison.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# This file is part of the polar2grid software package. Polar2grid takes
# satellite observation data, remaps it, and writes it to a file format for
#     input into another program.
# Documentation: http://www.ssec.wisc.edu/software/polar2grid/
"""Add a colortable to an existing GeoTIFF."""

import os
import sys

import numpy as np
import rasterio
from trollimage.colormap import Colormap


[docs] def load_color_table_file_to_colormap(ct_file): """Load a text colormap file and create a trollimage.Colormap object. If the provided pathname includes ``$POLAR2GRID_HOME`` it will be replaced with the current environment variable value of ``POLAR2GRID_HOME``. """ from satpy.enhancements import create_colormap p2g_home = os.getenv("POLAR2GRID_HOME", "") ct_file = ct_file.replace("$POLAR2GRID_HOME", p2g_home) ct_file = ct_file.replace("$GEO2GRID_HOME", p2g_home) cmap = create_colormap({"filename": ct_file}) return cmap
[docs] def create_colortable(ct_file_or_entries): """Create GDAL ColorTable object from Colormap object.""" if isinstance(ct_file_or_entries, str): ct_file_or_entries = load_color_table_file_to_colormap(ct_file_or_entries) if isinstance(ct_file_or_entries, Colormap): values = np.arange(256) new_colors = ct_file_or_entries.colorize(values) new_colors = np.clip(new_colors, 0.0, 1.0) ct_file_or_entries = ( (color_idx,) + tuple(np.round(new_colors[:, color_idx] * 255.0)) for color_idx in range(new_colors.shape[1]) ) ct_dict = {entry[0]: tuple(entry[1:]) for entry in ct_file_or_entries} return ct_dict
[docs] def add_colortable(gtiff_ds, ct_dict): num_bands = gtiff_ds.count if num_bands in (2, 4): # don't add a color table to alpha bands num_bands -= 1 for band_num in range(num_bands): gtiff_ds.write_colormap(band_num + 1, ct_dict)
[docs] def get_parser(): import argparse description = "Add a GeoTIFF colortable to an existing single-band GeoTIFF." parser = argparse.ArgumentParser(description=description) parser.add_argument("ct_file", help="Color table file to apply (CSV of (int, R, G, B, A)") parser.add_argument("geotiffs", nargs="+", help="Geotiff files to apply the color table to") return parser
[docs] def main(argv=sys.argv[1:]): parser = get_parser() args = parser.parse_args(argv) ct = create_colortable(args.ct_file) for geotiff_fn in args.geotiffs: gtiff_ds = rasterio.open(geotiff_fn, "r+") add_colortable(gtiff_ds, ct)
if __name__ == "__main__": sys.exit(main())