2010 U.S. Geological Survey (USGS) Topographic LiDAR: Mobile Bay, AL
This kmz file shows the extent of coverage for the 2010 USGS Mobile Bay lidar data.
USGS Contract: G10PC00026 Task Order Number: G10PD00578 LiDAR was collected at a nominal
pulse spacing of 2.0 meters for a 700 square mile area to the east of Mobile Bay,
either not previously surveyed using LiDAR sensors or where the collected data was
poor, while no snow was on the ground and rivers were at or below normal levels. The
goal of the NGOM LiDAR project in the post-Katrina environment is to provide scientific
knowledge and tools required to make optimal decisions about land resource use, management
practices, and future development in the northern Gulf of Mexico coastal zone. This
regional LiDAR elevation mapping data will be used for modeling, predicting landscape
change, promoting restoration of ecosystems, and mitigating risks associated with
anthropomorphic and natural hazards.
Cite this dataset when used as a source.
|Search and Download
|| Distributor information not available
| Point of Contact
Lidar Dataset Supplemental Information
- DOI/USGS > United States Geological Survey, U.S. Department of Interior
|Data Presentation Form:
|| Digital image
|Dataset Progress Status
|Data Update Frequency:
|| As needed
||Classified LAS files are used to show the manually reviewed bare earth surface. Any
additional classification is provided via automated macro functionality from proprietary
Photo Science TerraScan macros. These additional classifications include Class 4 -
Medium Vegetation and Class 5 - High Vegeation. This allows the user to create Intensity
Images, Break Lines, Raster DEM, and Triangular Irregular Networks.
||2010-02-20 to 2010-02-25
|Spatial Reference System:
|Spatial Bounding Box Coordinates:
|Spatial Coverage Map:
- remote sensing
- Baldwin County
- Escambia County
- Bon Secour
| Use Constraints
|| No constraint information available
|| Fee information not available.
|| Lineage statement not available.
| Processing Steps
- Applanix software was used in the post processing of the airborne GPS and inertial
data that is critical to the positioning and orientation of the sensor during all
flights. POSPac MMS provides the smoothed best estimate of trajectory (SBET) that
is necessary for Optech's post processor to develop the point cloud from the LiDAR
missions. The point cloud is the mathematical three dimensional collection of all
returns from all laser pulses as determined from the aerial mission. At this point
this data is ready for analysis, classification, and filtering to generate a bare
earth surface model in which the above ground features are removed from the data set.
The point cloud was manipulated within the Optech software; GeoCue, TerraScan, and
TerraModeler software was used for the automated data classification, manual cleanup,
and bare earth generation from this data. Project specific macros were used to classify
the ground and to remove the side overlap between parallel flight lines. All data
was manually reviewed and any remaining artifacts removed using functionality provided
by TerraScan and TerraModeler. All Class 2 LiDAR data inside of the collected breaklines
were then classified to Class 9 using TerraScan macro functionality. A buffer of 1
meter was also used around each hydro flattened feature. The breakline files were
then translated to ESRI Shapefile format using ESRI conversion tools. Data was then
run through additional macros to ensure deliverable classification levels matching
LAS ASPRS Classification structure. GeoCue functionality was then used to ensure correct
LAS Version. In house software was used as a final QA/QC check to provide LAS Analysis
of the delivered tiles.
- The NOAA Coastal Services Center (CSC) received topographic files in LAS format. The
files contained lidar elevation and intensity measurements. The data were received
in UTM Zone 16 (NAD83) coordinates and were vertically referenced to NAVD88 using
the Geoid09 model. The vertical units of the data were meters. CSC performed the following
processing for data storage and Digital Coast provisioning purposes: 1. The topographic
las files were converted from orthometric (NAVD88) heights to ellipsoidal heights
using Geoid09. 2. The horizontal coordinate system was converted from UTM (meters)
to Geographic (decimal degrees). 3. The data were converted to LAZ format.
- 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: 2013-03-28
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