Data Management Plan

This dataset is the bare earth lidar data for St. Johns County, Florida, acquired in early January and February of 2004. This data was collected to develop comprehensive countywide base mapping and perform other GIS enhancements to support master drainage planning, transportation planning, preliminary engineering and wetland preservation studies. The surveyed area included all of St. Johns County, approximately 610 square miles. Eighty-seven (87) flight lines of high density lidar data (average GSD is 3.3 feet) were obtained at an altitude of 3000 feet AGL. This data set contains only model keypoints (points that are a thinned data set that is intended to remove extraneous data such as trees and points that are deemed redundant to the final bare earth product) that are classified as ground points. As a result, there are a lower number of points than in a full mass point lidar data set; and it is recommended that the data be downloaded as points and used with a TIN (Triangulated Irregular Network) or similar algorithm to produce a bare earth surface.

This data was collected on the 1990 realization of NAD83. However, there is no EPSG code for that realization and the data have been tagged with the 1996 realization.

Original contact information:

Contact Name: Mike Campbell

Contact Org: St. Johns County Florida GIS

Title: St. Johns County GIS Manager

Phone: 904-209-0778

Email: gis@sjcfl.us

Process Steps:

• 2004-01-01 00:00:00 - The LiDAR data was acquired in 93 flight lines acquired in 6 sessions between January 17 and February 7, 2004 from an altitude of 3,000 feet above ground level (AGL) to provide an average ground sample distance (GSD) of 3.3 feet. Three concurrent airborne GPS base stations were used for each acquisition session. The ABGPS data were reduced using the GrafNav software package by Waypoint Consulting, Inc. The IMU data was reduced using the PosProc software package by Applanix Corporation. The initial lidar "point cloud" was derived through the ALS Post Processor software package by Leica Geosystems. The aircraft, lidar system and associated computer hardware and software are owned and operated by Woolpert LLP. Once the initial lidar "point cloud" was derived, Woolpert performed QC to look for any systematic error within the lidar flights using proprietary software. After systematic error was identified and removed, the individual lidar flights were clipped to remove overlap between adjacent flight lines and provide a homogeneous coverage over the project extents. Using the homogeneous coverage, above ground features were classified and removed using proprietary software to produce the bare-earth coverage.
• 2008-11-03 00:00:00 - The NOAA Office for Coastal Management (OCM) received the files in ASCII format. The data was in Florida State Plane Projection, NAVD88 vertical datum and the vertical units of measure were feet. OCM performed the following processing to the data to make it available within Digital Coast: 1. The data were converted from Florida State Plane East, Zone 0901 coordinates to geographic coordinates. 2. The data were converted from NAVD88 (orthometric) heights to GRS80 (ellipsoid) heights using Geoid 03. 3. The vertical unit of measure for the data was converted from feet to meters. (Citation: 2004 St. Johns County, Florida Lidar)
• 2023-10-30 00:00:00 - Data were converted to Cloud Optimized Point Cloud format to facilitate streaming .

This data can be obtained on-line at the following URL: https://coast.noaa.gov/dataviewer;