2005 USACE Post-Hurricane Dennis Topo/Bathy Project, Alabama and Florida Coasts
These data were collected by the Joint Airborne Lidar Bathymetry Technical Center
of Expertise using the CHARTS system. The data was collected in July 2005, along the
Alabama and Florida coastline. The data includes hydrographic and topographic data.
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:
|| As needed
||The data were collected to depict the elevations above and below water along the immediate
||2005-07-13 to 2005-07-25
|Spatial Reference System:
|Spatial Bounding Box Coordinates:
|Spatial Coverage Map:
- Gulf Shores
- Fort Walton
- Gulf Breeze
| Use Constraints
|| No constraint information available
|| Fee information not available.
|| Lineage statement not available.
| Processing Steps
- These data were collected using the CHARTS surveys system. It is owned by the Naval
Oceanographic Office and operated through contract. The system collects topographic
lidar data at 20kHz and hydrographic data at 3kHz. The system also collects RGB imagery
at 1Hz. Aircraft position, velocity and acceleration information are collected through
a combination of Novatel and POS A/V equipment. Raw data are collected and transferred
to the office for downloading and processing in SHOALS GCS software. GPS data are
processed using POSPac software and the results are combined with the lidar data to
produce 3-D positions for each lidar shot. These data are edited using Fledermaus
software where anomalous data are removed from the dataset. The edited data are unloaded
from SHOALS GCS, converted from ellipsoid to orthometric heights, based on the GEOID03
model, and split into greographic tiles covering approximately 5km each.
- The NOAA Coastal Services Center (CSC) received files in ascii format. The files contained
lidar intensity and elevation measurements. CSC performed the following processing
on the data to make it available within the Lidar Data Retrieval Tool (LDART): 1.
Each hydro/topo last return ascii file was converted to las files. Default values
for which there is no corresponding input were assigned as follows for each las elevation
data record: intensity = 0, retn = 1, nret = 1, class = 0 2. The las files were sorted
by latitude and the las header fields were updated.
- Times had originally been stored as POSIX seconds when converted to LAS. This was
switched to adjusted GPS time (GPS seconds - 1e9) to conform to the LAS 1.2 standard.
The data were also converted to LAZ format.
- For data managment purposes, the Coastal Services Center converted the data from NAVD88
elevations to ellipsoid elevations using Geoid 03.
- 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
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
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
the ellipsoid (either GRS80 or ITRF94), allowing for the ability to apply the most
up to date geoid model when transforming to orthometric heights.
Metadata Last Modified: 2014-03-14
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