Tyler de Jong is a researcher based in Whitehorse, Yukon with Global Water Futures at McMaster University. Email: tyler.dejong@mcmaster.caWatershed-scale landscape analysis includes many disciplines, including ecological, hydrological, and geographical sciences. e recent proliferation of free optical satellite imagery (FOSI) has changed the possibilities for the monitoring of environmental change at local and global scales. Many reviews exist for discipline-specific remote sensing applications; however, this article seeks to highlight the rapidly growing archive of FOSI and applied tools that can be used by all levels of users. Herein, ten techniques and eight applications of FOSI are reviewed, along with the specifications and limitations of various sources of FOSI. Although this review focuses on Western Canada, the democratization of FOSI is globally relevant, and the objective is to explain basic concepts via figures and reference materials to help summarize this rapidly changing field.
KEYWORDS free optical satellite imagery; remote sensing; watershed science; environmental monitoring; open dataRemote sensing is the science of obtaining information about an object from a distance. is information can be collected from terrestrial, aquatic, aerial, or satellite platforms. Optical imaging sensors aboard these platforms record image data consisting of emitted or reflected electromagnetic energy. Since 2008, the availability of free optical satellite imagery (FOSI) has grown exponentially since the United States Geological Survey (USGS) first opened its image archives (Woodcock et al., 2008). As such, the Earth is currently being imaged many times per day at a variety of spatial resolutions (Malenovský et al., 2012;Roy et al., 2014). e availability of FOSI has enabled the development of free online visualization tools (see Appendix A), free open source remote sensing soware (see Appendix B), and free analysis-ready remote sensing products (see Appendix C). e abundance of FOSI has empowered natural resource managers, researchers, and others to increase, and ultimately improve, the monitoring and quantification of watershed-scale environmental change.Review articles have addressed vegetation mapping (Xie et al., 2008), land cover classification (Phiri & Morgenroth, 2017), forest inventories , and large area mapping techniques (Gómez et al., 2016; Hansen & Loveland, 2012
IntroductionAbstract of: 1) fundamental concepts; 2) common datasets; 3) data portals; 4) processing techniques; and 5) applied examples of watershed-scale remote sensing. e objective is to provide readers new to satellite remote sensing with a comprehensive reference guide explained in plain language, and to provide advanced users with a helpful compilation of reference materials.is section provides a synthesis of fundamental concepts in Earth observation (EO) remote sensing science, with a focus on passive optical sensors that measure and record energy emitted from external sources (typically the sun). Earth observation satellites have ne...