a) JOIN FIELD(Input table=[mu_elev.shp]; Input join field=mu_FID_CMU; Join table=[veg_elev.shp]; Output join field=vg_FID_CMU; Join fields=vg_AVEG_M2, vg_ATOT_M2, vg_MEAN). Change the field names to "VG_ELEV" and "MU_ELEV" for the fields with the mean elevation for the vegetated area only and mean elevation for the entire marsh unit, respectively. Name fields "AVEG_M2" and "ATOT_M2" for vegetated and total area, respectively; and "MU_HFAR" and "VG_HFAR" for the percent (in decimal form) of the marsh unit, and of the vegetated portion, that has hydro-flattened area, respectively. Set MU_ELEV to -9999 if MU_HFAR is greater than 0.25; set VG_ELEV to -9999 if there is no vegetated area in the marsh unit or if VG_HFAR is greater than 0.25. Export to a new shapefile [mu_Elev_MA.shp].
b) Run Python script (marsv5.py) in ArcPro (v.2.4.1) to calculate metrics that quantify the distribution of marsh unit elevation values. Skewness ("SKWNSS") is the measure of asymmetry of the elevation distribution in the vegetated part of a marsh unit. Positive skewness values, i.e. right-skewed distributions, indicate clustering of elevation distributions towards lower elevations. Negative skewness values indicate a left-skewed distribution and clustering towards higher elevations. Lower third ("LOW3RD") is the percent of elevation values that fall within the lowest third of the elevation range within the vegetated part of a marsh unit. SKWNSS and LOW3RD parameters are calculated by applying the formulation of Raposa et al. (2016) to the elevation raster within the vegetated part of each marsh unit. If VG_ELEV= -9999, set SKWNESS and LOW3RD values to -9999.
c) SELECT BY ATTRIBUTES from [CMU_MA.shp] where "TYP"= 'vegetated,’ and join field "APGN_M2" from [CMU_MA.shp] to the feature dataset [mu_Elev_MA.shp] and rename this field "AVEG_M2."
Raposa, K. B., Wasson, K., Smith, E., Crooks, J. A., Delgado, P., Fernald, S. H., et al. (2016). Assessing tidal marsh resilience to sea-level rise at broad geographic scales with multi-metric indices. Biological Conservation, 204, 263–275. https://doi.org/10.1016/J.BIOCON.2016.10.015