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|
#!/usr/bin/env python3
# This program is a direct translation of the sample program
# "write_bitmask.c" bundled with the EPR-API distribution.
#
# Source code of the C program is available at:
# https://github.com/bcdev/epr-api/blob/master/src/examples/write_bitmask.c
"""Generates bit mask from ENVISAT flags information as "raw" image
for (e.g.) Photoshop.
Call::
$ python3 write_bitmask.py <envisat-product> <bitmask-expression>
<output-file>
Example to call the main function::
$ python3 write_bitmask.py MER_RR__2P_TEST.N1 \
'l2_flags.LAND and !l2_flags.BRIGHT' my_flags.raw
"""
import sys
import epr
def main(*argv):
if not argv:
argv = sys.argv
if len(argv) != 4:
print(
"""\
Usage:
python3 write_bitmask <envisat-product> <bitmask-expression>
<output-file>
where envisat-product is the input filename and bitmask-expression
is a string containing the bitmask logic and output-file is the
output filename.
Example:
MER_RR__2P_TEST.N1 'l2_flags.LAND and not l2_flags.BRIGHT'
my_flags.raw
"""
)
sys.exit(1)
product_file_path = argv[1]
bm_expr = argv[2]
image_file_path = argv[3]
# Open the product; an argument is a path to product data file
with epr.open(product_file_path) as product:
offset_x = 0
offset_y = 0
source_width = product.get_scene_width()
source_height = product.get_scene_height()
source_step_x = 1
source_step_y = 1
bm_raster = epr.create_bitmask_raster(
source_width, source_height, source_step_x, source_step_y
)
product.read_bitmask_raster(bm_expr, offset_x, offset_y, bm_raster)
with open(image_file_path, "wb") as out_stream:
bm_raster.data.tofile(out_stream)
print(f"Raw image data successfully written to {image_file_path!r}.")
print(
f"Data type is 'byte', size is {source_width} x {source_height} "
f"pixels."
)
if __name__ == "__main__":
main()
|
