Python for Geosciences: Raster bit masks explained (step by step)

Learn how to (correctly) use raster bit masks layers provided by satellite images as quality assessment bands

Due to changes in Medium.com policy concerning non-members reads, implemented in Sep 2023, this post is now freely available on geocorner.net: https://www.geocorner.net/post/python-for-geosciences-raster-bit-masks-explained-step-by-step

Introduction

Welcome back to the 4th part of the Python for Geosciences series. In the previous post we have covered how to extract the bands values to proceed a simple spectral analysis. Imagine, however, that our final objective is to automatically monitor the reflectance spectra of a specific area of interest. This could be a crop, a forest, a lake or any other target and the goal is to check the evolution of the spectral reflectance of this area over the time (this can be used, for example, to identify a specific type of crop, monitor the evolution of a water parameter, etc.). This task could be easily automated (we will see automation in the next post), but there is an issue we should take care of if we want to run this kind of monitoring in the “auto-pilot” mode. Undesired pixels such as clouds and shadows can block the view of the satellite sensor and…