Data Management Plan

This data set is one component of a digital terrain model (DTM) for the Southwest Florida Water Management District's

FY2006 Digital Orthophoto (B089) and LiDAR Project (L470/L471), encompassing approximately 1,216 square miles across

Citrus and Sumter counties. The 2006 LiDAR dataset is comprised of 3-D masspoints delivered in the LAS file format

based on the District's 5,000' by 5,000' grid (1,356 cells). The other DTM component is 2-D and 3-D breakline features

in the ESRI ArcGIS Personal Geodatabase format. In accordance with the 2006 SWFWMD Topographic Database Design,

the following breakline features are contained within the database: closed water bodies (lakes, reservoirs, etc)

as 3-D polygons; linear hydrographic features (streams, canals, swales, embankments, etc) as 3-D breaklines;

coastal shorelines as 3-D linear features; edge of pavement road features as 3-D breakines; soft features

(ridges, valleys, etc.) as 3-D breaklines; obscured vegetation polygons as 2-D polygons; overpasses and bridges

as 3-D breaklines; 1-foot contours for visualization purposes; and island features as 3-D polygons. This data falls

in Citrus and Sumter Counties.

Intensity values, or the measure of reflectance of the laser are also captured.

Breakline features were captured to develop a hydrologically correct DTM. Contours (1-foot) were generated from

the DTM that meet the National Map Accuracy Standards for 2-foot contours (FEMA specifications). Bare earth LiDAR

masspoint data display a vertical accuracy of at least 0.3-feet root mean square error (RMSE) in open unobscured areas

Original contact information:

Contact Name: Mapping and GIS Section

Contact Org: Southwest Florida Water Management District

Phone: 352.796.7211

Process Steps:

• 2007-01-05 00:00:00 - The LiDAR data was acquired using a Leica ALS50 from an altitude of 2,400' above ground level to provide an nominal ground sample distance of 2.4-feet. The scanner field of view was 28-degrees, and the scan rate was 46-hertz. First and last return data was collected along with the signal return intensity. A total of 278 flights of LiDAR data were acquired. Flight lines were flown with a 30% sidelap, providing a line-to-line swath width of 957-feet. Thirty (30) Two redundant airborne GPS bases stations were utilized during the data acquisition with maximum line-of-sight distance between the base station and aircraft of 20-km. The LiDAR data was reduced using Grafnav (Waypoint Consulting) for GPS post-processing, PosProc (Applanix Crop) for IMU processing, ALS50 Post Processor (LH Systems) to initial LiDAR processing, TerraScan (Terrasolid) for initial point classification, and proprietary Woolpert developed software for refining the point classification and QC. The LAS files contain 5 classifications: 1 = unclassified; 2 = ground; 9 = water; and 10 = photogrammetric mass points and 11=swamp/wetland points. The class 1 consists of all points not on the ground. Class 2 consists of bare earth points. Class 9 points are those points falling within lake/pond polygons. Class 10 consists of supplementary mass points that were photogrametrically compiled on points features suchs as peaks or pits, and they were created to maintain the accuracy of the DTM. Class 11 consists of points within swamps and/or wetlands polygons classified as ground. For a complete description of survey methods, processing methods, software, system parameters, and accuracy analysis, see the Florida MTS Report of Specific Purpose Survey, North District LiDAR DTM Project (L470/L471), dated January 2007.
• Metadata imported.
• 2008-01-01 00:00:00 - The NOAA Office for Coastal Management (OCM) received the the files in LAS format. The files contained Lidar elevation measurements. The data was in Florida State Plane Projection and NAVD88 vertical datum. OCM performed the following processing to the data to make it available within the Digital Coast Data Access Viewer (DAV): 1. The data were converted from Florida State Plane West coordinates to geographic coordinates. 2. The data were converted from NAVD88 (orthometric) heights to GRS80 (ellipsoid) heights using Geoid03. 3. The LAS data were sorted by latitude and the headers were updated.

This data can be obtained on-line at the following URL:

https://coast.noaa.gov/dataviewer

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