calculate toa reflectance for Planet Labs data - not an ideal script, but you get the idea

toa_reflectance.py

import os
import argparse

from bs4 import BeautifulSoup
import rasterio


SUFFIX = '_BGRN_Analytic'
BASEPATH = '/Users/robinkraft/gitlab/change/hackathon/robin/data/'


def parse_xml(path):
    xml = open(path, 'r').read()
    soup = BeautifulSoup(xml, 'lxml')
    return soup


def get_coefs(soup):
    raw_coefs = soup.find_all('ps:reflectancecoefficient')
    coefs = {}

    for i in range(len(raw_coefs)):
        idx = i + 1
        coefs[idx] = float(raw_coefs[i].get_text('ps:reflectancecoefficient'))

    return coefs


def convert2ref(band, band_num, coefs):
    coef = coefs[band_num]

    return band * coef


def rad2ref(img, coefs):
    bands = {}

    for i in range(img.count):
        band_num = i + 1
        band = img.read(band_num)

        bands[band_num] = convert2ref(band, band_num, coefs)

    return bands


def gen_paths(img_id, suffix, basepath):
    xml_path = '{}{}_metadata.xml'.format(img_id, suffix)
    xml_path = os.path.join(basepath, xml_path)

    src_path = '{}{}.tif'.format(img_id, suffix)
    src_path = os.path.join(basepath, src_path)

    out_path = '{}{}_reflectance.tif'.format(img_id, suffix)
    src_path = os.path.join(basepath, src_path)

    return dict(xml=xml_path, src=src_path, out=out_path)


def save_ref(src, out_path, coefs):
    kwargs = src.meta

    # Update kwargs (change in data type)
    kwargs.update(
        dtype=rasterio.float32,
        count = src.count)

    bands = rad2ref(src, coefs)

    with rasterio.open(out_path, 'w', **kwargs) as dst:
        for b in bands.keys():
            dst.write_band(b, bands[b].astype(rasterio.float32))

    pass


def main(img_id):

    paths = gen_paths(img_id, SUFFIX, BASEPATH)

    soup = parse_xml(paths['xml'])
    coefs = get_coefs(soup)

    src = rasterio.open(paths['src'])


    save_ref(src, paths['out'], coefs)

    return


if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('--id', help='Image id for the image to be processed')

    args = parser.parse_args()

    main(args.id)