2009 Chatham County Georgia Lidar
This kmz file shows the extent of coverage for the 2009 Chatham County, GA lidar data
LiDAR generated point cloud acquired in spring 2009 for Chatham County, Georgia for
the Metropolitan Planning Commission. The data are classified as follows: Class 1
= Unclassified. This class includes vegetation, buildings, noise etc. Class 2 = Ground
Class 9 = Water This data is for planning purposes only and should not be used for
legal or cadastral purposes.
Cite this dataset when used as a source.
|Search and Download
|| Distributor information not available
| Point of Contact
Documentation links not available.
|Data Presentation Form:
|| Digital image
|Dataset Progress Status
|Data Update Frequency:
||Support of FEMA's Floodplain Map Modernization Program and Florida Division of Emergency
Management Disaster standards. Collection parameters are as follows: Flight Altitude
- 1100m (agl) Repetition Rate - 93300 kHz; Scan Frequency - 44.5kz Airspeed - 100-120
knots Field of View - 30 degrees Avg. Point Spacing 0.57m Flightline Spacing - 294m
||LiDAR points used in conjunction with LiDAR derived breaklines to determine a DTM
|| Unknown to Unknown
|Spatial Reference System:
|Spatial Bounding Box Coordinates:
|Spatial Coverage Map:
- United States
- Chatham County
| Use Constraints
|| No constraint information available
|| Fee information not available.
|| Lineage statement not available.
- Sanborn Map Company
- DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department
| Processing Steps
- The ABGPS, IMU, and raw Leica ALS-50 LiDAR data are integrated into the LEICA ALS
post processor software. The resultant file is in a LAS binary file format. The LAS
file version 1.1 formats 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 geodetic coordinates
referenced to the NAD83 horizontal datum and GRS80 vertical datum.
- 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. The LiDAR mass points were delivered in American Society
for Photogrammetry and Remote Sensing LAS 1.1 format. The header file for each dataset
is complete as define by the LAS 1.1 specification. In addition the following fields
are included: Flight Date Julian, Year, and Class. The LAS files do not include an
overlap class. The data was classified as follows: Class 1 = Unclassified. This class
includes vegetation, buildings, noise etc. Class 2 = Ground Class 7 = noise (outliers)
Class 9 = Water
- Conversion from Geodetic coordinates, NAD83 into State Plane coordinates (U.S. Survey
Feet) NAD83 and conversion from ellipsoid heights (meters) into orthometric heights
(U.S. Survey Feet).
- Ground points were extracted from the Lidar dataset and used in conjunction with breaklines
to hydrologically enforce a DTM surface and converted to an ESRI GRID (1m pixels)
- The NOAA Coastal Services Center (CSC) 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. CSC 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
converted from NAVD88 (orthometric) heights in feet to GRS80 (ellipsoid) heights in
meters using Geoid 03. 3. The data were filtered to remove outliers. 4. The LAS data
were sorted by latitude and the headers were updated.
- The NOAA National Geophysical Data Center (NGDC) received lidar data files via ftp
transfer from the NOAA Coastal Services Center. The data are
currently being served via NOAA CSC Digital Coast at http://www.csc.noaa.gov/digitalcoast/.
The data can be used to re-populate the system. The data are archived in LAS
or LAZ format. The LAS format is an industry standard for LiDAR data developed by
the American Society of Photogrammetry and Remote Sensing (ASPRS); LAZ is a loseless
compressed version of LAS developed by Martin Isenburg (http://www.laszip.org/). The
data are exclusively in geographic coordinates (either NAD83 or ITRF94). The data
are referenced vertically to the ellipsoid (either GRS80 or ITRF94), allowing for
the ability to apply the most up to date geoid model when transforming to orthometric
Metadata Last Modified: 2013-06-04
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