Routine for extracting sea ice lead coordinates at 5 km geodesic steps from Level1B thermal infrared MODIS imagery.
The notebook Lead_Extraction.ipynb shows an example routine to extract lead coordinates from a composite image of the Beaufort and Chukchi Seas ice cover on February 20, 2013 from Level1B thermal infrared (band 31) Terra/MODIS imagery files (https://doi.org/10.5067/MODIS/MOD021KM.061, https://doi.org/10.5067/MODIS/MOD03.061). For this example, files were downloaded from the NASA LAADS DAAC and stored locally. All that is needed to run this example routine are the MODIS imagery files listed in MODIS_file_list.txt and the python packages used in the notebook.
There are three main sections of the notebook.
Open hdf files of L1B thermal infrared MODIS imagery and save to a projected image in grayscale.
Use interactive figure window to manually select some lead coordinates with mpl_point_clicker and use sci-kit image active contour model to fill in additional coordinates between selected points based on the brightness contrast across leads in thermal images.
Use geopy and metpy to re-index/interpolate lead coordinates to fall along 5-km geodesic steps.
Additional instructions provided directly in the notebook.