Data Management Plan

Dewberry collected 1200 square miles of lidar data in Hillsborough County, Florida. The nominal pulse spacing for this project was 1 point every 0.25 meters or a nominal pulse density of 16 points per square meter. Dewberrry used proprietary procedures to classify the LAS according to project specifications: 1-Unclassified, 2-Ground, 6-Building Rooftops, 7-Low Noise, 9-Water, 17- Bridge Decks, 18-High Noise. Geometrically unreliable points, ground points within 2 feet of breaklines, and ground points within 3 feet of buiding rooftops have been identified with the Withheld Flag. Overage points have been identified with the Overlap Flag. The lidar data were combined with 3D breaklines compiled by Dewberry to create hydro-enforced bare-earth DEMs. The data were tiled according to the Florida Statewide Lidar Index tiling scheme with each tile covering an area of 5,000 feet by 5,000 ft.

Lineage Statement:
The NOAA Office for Coastal Management (OCM) downloaded the DEM .img file from the Southwest Florida Water Management District (SWFWMD).

Process Steps:

• 2019-04-01 00:00:00 - Class 2, ground, lidar points are exported from the LAS files into an Arc Geodatabase (GDB) in multipoint format. The 3D breaklines, water bodies, hydrographic features, and islands are imported into the same GDB. 2D building footprints are buffered by 3 feet and the highest ground elevation within the buffered footprint is applied to the entire footprint. The 3D building footprints are then imported into the same GDB as the multipoints and other 3D breaklines. An ESRI Terrain is generated from these inputs. The surface type of each input is as follows: Ground Multipoint: Masspoints Water bodies: Hard Replace Hydrographic feature : Hard Line Islands : Hard Line Building Footprint: Hard Replace The ESRI Terrain is converted to a raster. The raster is created using linear interpolation with a 2.5 foot cell size. The DEM is reviewed with hillshades in both ArcGIS and Global Mapper. Hillshades allow the analyst to view the DEMs in 3D and to more efficiently locate and identify potential issues. Analysts review the DEM for missed lidar classification issues, incorrect breakline elevations, incorrect hydro-flattening or hydro-enforcement, and artifacts that are introduced during the raster creation process. The corrected and final DEM is clipped to individual tiles. Dewberry uses a proprietary tool that clips the DEM to each tile located within the final Tile Grid, names the clipped DEM to the Tile Grid Cell name, and verifies that final extents are correct. All individual tiles are loaded into Global Mapper for the last review. During this last review, an analsyt checks to ensure full, complete coverage, no issues along tile boundaries, tiles seamlessly edge-match, and that there are no remaining processing artifacts in the dataset.
• The NOAA Office for Coastal Management (OCM) downloaded 1 raster DEM file in .img format from the Southwest Florida Water Management District (SWFWMD). The data were in Florida State Plane West NAD83(2011), US survey feet coordinates and NAVD88 (Geoid12B) elevations in feet. The bare earth raster file was at a 2.5 feet grid spacing. OCM performed the following processing on the data for Digital Coast storage and provisioning purposes: 1. Used internal an script to assign the EPSG codes (Horizontal EPSG: 6443 and Vertical EPSG: 6360) and convert the .img file to GeoTiff format. 2. Copied the file to https.

Data is available online for bulk and custom downloads.