Data Management Plan (Deprecated)

The Light Detection and Ranging (LiDAR) LAS dataset is a survey of Fulton County. The Fulton County LiDAR Survey project area consists of approximately 690.5 square miles. The LiDAR point cloud was flown at a density sufficient to support a maximum final post spacing of 5 meters for unobscured areas. 3001 Inc. acquired 75 flightlines between March 3, 2006 and March 6, 2006 and 120 flightlines were reflown between July 29, 2006 and August 4, 2006. The data was divided into 5000' by 5000' foot cells that serve as the tiling scheme. The Fulton County LiDAR Survey was collected under the guidance of a Professional Mapper/Surveyor.

Original contact information:

Contact Org: Ayres Associates

Phone: 608-443-1200

Process Steps:

• 2010-04-01 00:00:00 - The ABGPS, IMU, and raw scans are integrated using proprietary software developed by the Leica Geosystems and delivered with the Leica ALS50 System. The resultant file is in a LAS binary file format. The LAS file version 1.0 format can be easily transferred from one file format to another. It is a binary file format that maintains information specific to the LiDAR data (return#, intensity value, xyz, etc.). The resultant points are produced in the State Plane Georgia West (FIPS 1002) coordinate system, with units in feet and referenced to the NAD83 horizontal datum and NAVD88 vertical datum. Fulton County LiDAR Point Cloud data sets LAS 1.0 file format. The unedited data are classified to facilitate the application of the appropriate feature extraction filters. A combination of proprietary filters are applied as appropriate for the production of bare earth digital terrain models (DTMs). Interactive editing methods are applied to those areas where it is inappropriate or impossible to use the feature extraction filters, based upon the design criteria and/or limitations of the relevant filters. These same feature extraction filters are used to produce elevation height surfaces. Filtered and edited data are subjected to rigorous QA/QC. Very briefly, a series of quantitative and visual procedures are employed to validate the accuracy and consistency of the filtered and edited data. Ground control is established by 3001, Inc. and GPS-derived ground control points (GCPs) points in various areas of dominant and prescribed land cover. These points are coded according to landcover, surface material and ground control suitability. A suitable number of points are selected for calculation of a statistically significant accuracy assessment as per the requirements of the National Standard for Spatial Data Accuracy. A spatial proximity analysis is used to select edited LiDAR data points within a specified distance of the relevant GCPs. A search radius decision rule is applied with consideration of terrain complexity, cumulative error and adequate sample size. Accuracy validation and evaluation is accomplished using proprietary software to apply relevant statistical routines for calculation of Root Mean Square Error (RMSE) and the National Standard for Spatial Data Accuracy (NSSDA) according to Federal Geographic Data Committee (FGDC) specifications. The LiDAR mass points were delivered in American Society for Photogrammetry and Remote Sensing LAS 1.0 format. The header file for each dataset is complete as define by the LAS 1.0 specification. In addition the following fields are included: Flight Date Julian, Year, and Class. The LAS files do not include overlap. The data was classified as follows: Class 1 = Unclassified. This class includes vegetation, buildings, noise etc. Class 1 = Unclassified, Class 2 = Ground. The datasets were delivered in Fulton County's standard 5000' by 5000' tiling scheme. The tiles are contiguous and do not overlap. The tiles are suitable for seamless topographic data mosaics that include no "no data" areas. The names of the tiles are left padded with zeros as required to achieve a five character length and all files utilize the LAS file extension.
• 2012-08-01 00:00:00 - The NOAA Office for Coastal Management (OCM) received the files in las format. The files contained lidar elevation and intensity measurements. The data were in GA State Plane coordinates and NAVD88 (orthometric) heights in feet. OCM performed the following processing for data storage and Digital Coast provisioning purposes: 1. The data were converted from GA State Plane coordinates to geographic coordinates. 2. The data were filtered to remove outliers below 660 and 2050 feet. 3. The data were converted from NAVD88 (orthometric) heights in feet to GRS80 (ellipsoid) heights in meters using Geoid 03. 4. Attempts were made to find the water class (9) though data received had water reclassed to unclassed along with a number of ground points, therefore processing to pull out only water classes were thwarted. 5. 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

The data set is dynamically generated based on user-specified parameters.

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