E them viable to use for ecological analyzes [61]. Sentinel-2 [62], a European Space Agency's

E them viable to use for ecological analyzes [61]. Sentinel-2 [62], a European Space Agency’s satellite, could be in comparison with Landsat satellites in terms of spatial and spectral resolution. Sentinel-2 was initially designed for land monitoring [63] but has been utilized for monitoring oceans (and more especially coral reefs bleaching) and mapping benthic habitat [640]. Distinct spectral bands of Sentinel-2, like SWIR-cirrus and water vapor bands, are particularly valuable for cloud detection and GS-626510 Data Sheet removal algorithms [715]. One main benefit of Landsat and Sentinel-2 satellites is that their data are open access. Having said that, these satellites are defined as “low-resolution”, using a resolution of tens of meters which may perhaps be a important weakness when attempting to map and to classify the fine and complicated distribution of coral reef colonies. Using a typical spatial resolution of various meters, medium-resolution satellites are additional accurate than the aforementioned satellites. Well-known medium-resolution satellites are SPOT-6 [76,77] and RapidEye [780], with respectively four and five bands. A significant strength of RapidEye is that the image information are created by a constellation of five identical satellites, thus giving images at a high frequency (worldwide revisit time of one day). Note nevertheless that as much as now, RapidEye has not been located in current literature for coral mapping. The principle of working with numerous comparable satellites can also be found with all the PlanetScope constellation, composed of 130 Planet Dove satellites. Their total revisit time is less than a single day, and they will be found in GNE-371 Protocol several current coral mapping research [815].Remote Sens. 2021, 13,5 ofTable 1. Comparison of some characteristics on the most common multispectral satellites. Excepted for PlanetScope and RapidEye, all of the satellites include a panchromatic band which doesn’t seem in the column “Spectral bands”. Image pricings have been recovered from the internet site wwww.apollomapping.com, accessed on February 2021. Satellite Name Landsat-6 ETM Spectral Bands four VNIR 2 SWIR 1 thermal infrared four VNIR 2 SWIR 1 thermal infrared four VNIR 3 SWIR 1 deep blue 4 VNIR Sentinel-2 six red edge and SWIR three atmospheric PlanetScope RapidEye (5 satellites) SPOT-6 GaoFen-2 GeoEye-1 IKONOS-2 Pleiades-1 Quickbird-2 WorldView-2 panchromatic 4 VNIR panchromatic 5 VNIR 4 bands: blue, green, red, near-infrared 4 bands: blue, green, red, near-infrared 4 bands: blue, green, red, near-infrared 4 bands: blue, green, red, near-infrared four bands: blue, green, red, near-infrared 4 bands: blue, green, red, near-infrared eight VNIR 8 VNIR eight SWIR 12 CAVIS Resolution (at Nadir) 15 m panchromatic 30 m VNIR and SWIR 120 m thermal 15 m panchromatic 30 m VNIR and SWIR 60 m thermal 15 m panchromatic 30 m VNIR and SWIR 30 m deep blue 10 m VNIR 20 m red edge and SWIR 60 m atmospheric panchromatic 3.7 m multispectral panchromatic 5 m multispectral 1.5 m panchromatic six m multispectral 0.81 m panchromatic 3.24 m multispectral 0.41 m panchromatic 1.65 m multispectral 0.82 m panchromatic three.2 m multispectral 0.7 m panchromatic 2.8 m multispectral 0.61 m panchromatic two.4 m multispectral 0.46 m panchromatic 1.84 m multispectral 0.31 m panchromatic 1.24 m VNIR 3.7 m SWIR 30 m CAVIS Revisit Time 16 days Pricing FreeLandsat-7 ETM16 daysFreeLandsat-8 OLI16 daysFree10 daysFree1 day1 day 1 days 5 days two days 3 days 1 days 2 days 1.1.7 days1.8 /km2 1.28 /km2 four.75 /km2 4.five /km2 17.five /km2 10 /km2 12.five /km2 17.5 /km2 17.five /kmWorldView-1.5 days22.five /kmF.