bryanlandia / pymasker

generate masks from Landsat 8 and MODIS land product QA band

pymasker

Pymasker is a python package to generate various masks from the Landsat 8 Quality Assessment band and MODIS land products.

Installation

The package can be shipped to your computer using pip.

pip install pymasker

Or just install it with the source code.

python setup.py install

This package depends on numpy and GDAL.

An ArcMap python toolbox based on this package could be find here.

Use Example

Python

For Landsat 8 Quality Accessment band

from pymasker import LandsatMasker
from pymasker import LandsatConfidence

# load the QA band directly
masker = LandsatMasker('LC80170302014272LGN00_BQA.TIF')

# algorithm has high confidence that this condition exists (67-100 percent confidence)
conf = LandsatConfidence.high

# Get mask indicating cloud pixels with high confidence
mask = masker.get_cloud_mask(conf)

# save the result
masker.save_tif(mask, 'result.tif')

For MODIS land products

from pymasker import ModisMasker
from pymasker import ModisQuality

# load the QA band directly
masker = ModisMasker('MOD09GQ.A2015025.h12v04.005.2015027064556.hdf')

# Corrected product produced at ideal quality for all bands.
quality = ModisQuality.high

# Create a MODIS QA masker
mask = masker.get_qa_mask(quality)

# save the result
masker.save_tif(mask, 'result.tif')

Command Line

pymasker -s landsat -i landsat.tif -o mask.tif -c high -t cirrus

General parameters:

-s, --source SOURCE
                      source type: landsat, modis
-i, --input INPUT
                      input image file path
-o, --output OUTPUT
                      output raster path

Landsat parameters:

-c, --confidence CONFIDENCE
                      level of confidence that a condition exists in a landsat image: high, medium, low, undefined, none
-t, --target TARGET
                      target object: cloud, cirrus, water, vegetation, snow

MODIS parameters:

-q, --quality QUALITY
                      Level of data quality of MODIS land products at each pixel: high, medium, low, low_cloud

More Detail

The following two articles explains the mechanism behind the tool in detail.

• Landsat 8 Quality Assessment band

• MODIS land products

For JavaScript Developer

node-qa-masker provides the same masking functionality in NodeJS.

Change Log

• 0.3.2

  • Add get_fill_mask() to LandsatMasker (thanks to kbasten)

• 0.3.1

  • Simplify the initialization of ModisMasker

• 0.3.0

  • BREAKING CHANGE change most class and function names according to pep8
  • add command line tool