AUTHOR=Small Christopher TITLE=Grand Challenges in Remote Sensing Image Analysis and Classification JOURNAL=Frontiers in Remote Sensing VOLUME=1 YEAR=2021 URL=https://www.frontiersin.org/journals/remote-sensing/articles/10.3389/frsen.2020.605220 DOI=10.3389/frsen.2020.605220 ISSN=2673-6187