georefing.py

Overview

georefing.py is a Python script designed to georeference netCDF files containing reflectance data, regardless of the UTM zone, particularly designed to work with Polymer outputs. This script uses python libraries: xarray, rasterio, numpy, and pyproj to convert geographical coordinates from individual netCDF layers into UTM projection, creating georeferenced GeoTIFF files for specified bands (RW: 440, 480, 560, 655, and 865).

Features

• Georeferences netCDF files containing reflectance data of various wavelengths/bands.
• Dynamically determines the appropriate UTM zone based on the mean longitude of the input netCDF.
• Supports selecting specific bands for georeferencing (using a binary string input "XXXXX").
• Outputs GeoTIFF files organized into a specified directory.

Requirements

• Python 3.12 (or the latest version)

• Required Python packages:

  • xarray
  • rasterio
  • numpy
  • pyproj

You can install the required packages using pip:

pip install xarray rasterio numpy pyproj

Usage

To use this code, navigate to the root directory of the repository and run the script:

./run_geo.sh <optional_debugging> <input_nc_file> <output_directory> <band_selection>

Where,

1. Optional Debugging (-d): Use this if you want to see debugging printouts. This argument is optional!

2. Input netCDF File: Specify the .nc file to be georeferenced - either relative or absolute paths.

3. Output Directory: Specify the name of the directory in which the georeferenced .tif files will be placed. If a directory has been specified but doesn't exist, it will be created.

4. Band Selection: Use a binary string to indicate which bands need to be georeferenced, in order from largest band to smallest. For example, a band code of 11001 will georeference bands RW865, RW655, and RW440.

Example Command

./run_geo.sh -d example_nc_file.nc ../georeferenced_files 10101

This command takes example_nc_file.nc, georeferences bands RW865, RW560, and RW440, and saves the outputs in the georeferenced_files directory (one level above the current directory).

Code Structure

Here are the main functions of the script and what they do:

• parse_bands(bands): Converts a binary string into a list of boolean values that indicate which bands to process.

• get_out_proj(longitudes, latitudes): Determines the UTM projection using the mean longitude and latitude of the input data.

• debug_print(*args, kwargs): Outputs debug messages with timestamps to track down any errors.

• main(): The main function that loads the input imagery, selects the desired bands, transforms the coordinates, and saves the output as GeoTIFF files.

Contact

For any questions or suggestions, you can reach out to me at sydney.j.baratta@usace.army.mil or sydney.baratta@maine.edu.

Happy imagery processing!!