Everglades Depth Estimation Network (EDEN) October 2011 Digital Elevation Model (DEM)

This is the 2nd release of the fourth version of an Everglades Depth Estimation Network (EDEN) digital elevation model (DEM) generated from certified airborne height finder (AHF) and airboat collected ground surface elevations for the Greater Everglades Region. Collectively, these data are referred to as "High Accuracy Elevation Data" (HAED). Inconsistencies in available greater Everglades boundary files resulted in a missing elevation value for 1 cell along the western boundary of WCA3s. In this release, that single cell was "filled" with a value of 2.19682 meters as determined through the kriging process summarized below. As was the case with the 1st release (EDEN_em_JA10), this version differs from the previous elevation model (EDEN_EM_OCT07) in several ways. First, the kriging algorithm applied to newly modeled subareas was changed from ordinary to universal kriging - resulting in slightly lower errors during cross-validation and accuracy assessment. Second, a previously omitted area in the northwestern corner of the Everglades National Park (ENP) and southern portion of Big Cypress National Preserve has been filled. Third, to increase accuracy in WCA1, the most challenging EDEN subarea from an elevation modeling standpoint, the Conservation area is subdivided into 4 zones (Northern, Central, Southwest and Southeast). Boundaries between the North, Central and two Southern zones is based upon landscape units defined through the CERP. The landscape unit representing approximately the southern third of WCA1 was further divided into two zones (east and west) based on marked changes in slope and aspect data generated from a DEM of the southern landscape unit as a whole. Division of WCA1 into 5 zones reduces errors estimated by comparing DEM modeled water depths with those measured by EDEN Principal Investigators in the field. Subdivision of the south landscape unit into east and west zones resulted in lower error estimates for the eastern subzone (i.e., southeast) without significantly affecting (i.e., improving or degrading) the quality of the western subzone - an area where DEM modeling is most challenging. Finally, to reduce artificial breaks in elevation along WCA1 subarea boundaries, models were overlapped by 1 cell at these boundaries and, for the North, Central and South zone boundaries, overlapping model values were averaged. For the boundaries between the Southwest and Southeast zones, cell values were "blended" based on weighted distance from the boundary edge. Finally, points along the North / Central and Central / South zone edges were subjectively selected and changed by adding or subtracting 0.03 meters (3 cm) to particular cells. This slightly reduces apparent artifacts without drastically affecting the integrity of the model. The EDEN offers a consistent and documented dataset that can be used to guide large-scale field operations, to integrate hydrologic and ecological responses, and to support biological and ecological assessments that measure ecosystem responses to Comprehensive Everglades Restoration Plan. To produce historic and near-real time maps of water depths, the EDEN requires a system-wide DEM of the ground surface.

This file is intended specifically for use in the EDEN applications software. Therefore, it is a modification of the EDEN DEM released in January of 2010 (i.e., eden_em_ja10). The released January 2010 data was modified by converting elevation values from meters (m) to centimeters (cm). In a previous release of this data set (eden_em_cm_ja10-notch) data was removed from the southern Big Cypress National Preserve and northwestern Everglades National Park area so that the DEM boundary matched the EDEN boundary. However, a new version of the EDEN water surface boundary has been released in October 2011, and provided for the release of eden_em_cm_ja10 which has the area of southern Big Cypress National Preserve and northwestern Everglades National Park filled in so that it now matchs the current water surface model in that area. Aside from this difference in units, the following data documentation applies.