AgsSAT Multiannual (2017-2021) Sentinel-2 GeoMAD Composites

AgsSAT Multiannual (2017-2021) Sentinel-2 GeoMAD Composites The 2,815 images available for the state of Aguascalientes, Mexico for the years 2017 to 2021 were processed using the Open Data Cube (ODC) platform [Lewis et al. (2017), Gavin et al. (2018), https://www.opendatacube.org/]. These images correspond to multiple coverages of the region of interest. The images were then used to generate cloud-free annual composites by applying geometric median (geomedian) algorithm, as defined in [Roberts et al. (2017)]. Geomedian algorithm produces a pixel-level summary for every pixel, in this case this means that each summary corresponds to a 10m x 10m region in the territory and its observations throughout a calendar year. All these summary pixels form a 12-band (coastal aerosol, blue, green, red, vegetation red edge 5, vegetation red edge 6, vegetation red edge 7, near-infrared, narrow nir, water vapor, swir1 and swir2) composite of the state of Aguascalientes. Another product called GeoMad was generated, which calculates the robust dispersion statistic called MAD, as defined in [Roberts, D., Dunn, B., & Mueller, N. (2018)]. In the resulting image composite, each of the three-pixel bands represents the variation over three distances: Spectral Distance (smad), Euclidean Distance (emad) and the Bray-Curtis Distance (bcmad). More bands were generated to represent different environmental conditions during the study years (2017-2021), these conditions can be captured by analyzing various combinations of bands, these combinations are also called spectral indices, which allow detecting vegetation, presence of water, urbanization, etc., Finally, 28 indices divided into 4 categories were calculated: Vegetation Indices (Atmospherically Resistant Vegetation Index, Kaufman 1972) (Enhanced Vegetation Index, Huete 2002): (Modified Soil Adjusted Vegetation Index, Qi Et Al. 1994) (Normalized Difference Chlorophyll Index, Mishra & Mishra, 2012) (Normalised Difference Moisture Index, Gao 1996) (Normalized Difference Vegetation Index, Rouse 1973) (Optimized Soil Adjusted Vegetation Index, Rondeaux. 1996) (Simple Ratio Vegetation Index Jordan, C.F.1 969) (Soil Adjusted Vegetation Index, Huete 1988) (Visible Atmospherically Resistant Index, Gittleson 2002) Built-up Indexes (Band Ration For Built-up Area, Waqar 2012) (Built-up Area Extraction Index, Bouzekri 2015) (Built-up Index, He Et Al. 2010) (Index-based Built-up Index, Xu 2008) (New Built-up Index, Jieli Et Al. 2010) (Normalized