U.S. Geological Survey
NOAA National Ocean Service
USGS Center for Coastal and Watershed Studies
20060407
Tampa Bay topographic/bathymetric/LIDAR DEM
SDE raster digital data
http://chartmaker.ncd.noaa.gov/bathytopo/
This data set is a hybrid elevation model created from NOAA bathymetry, and USGS topography and LiDAR.
This data set is intended for geospatial applications that require seamless land elevation and water depth information in coastal environments.
1945
2004
ground condition
As needed
-82.875000
-82.375000
28.125000
27.375000
none
elevation
mapping
bathymetry
DEM
digital elevation model
topography
LIDAR
Experimental Advanced Airborne Research Lidar
EAARL
aerial digital photography
submerged topography
benthic cover types
process
derived surface
bare earth elevation
first return elevation
water thickness
sea surface directional wave spectrum
ALPS
Airborne Lidar Processing System
U.S Department of Commerce, 1987, Codes for the identification of the States, the District of Columbia and the outlying areas of the United States, and associated areas (Federal Information Processing Standard 5-2): Washington, D. C., NIST
FL
Florida
Coastal Florida
Tampa Bay
Tampa
Big Shoal
Coquina Key
Hillsborough Bay
Old Tampa
Cockroach Bay
Feather Sound
Pelican Cove
Terra Ceia
USGS Geographic Names Information System
Tampa Bay
none
Florida
Hillsborough County
Pinellas County
Manatee County
none
Hillsborough County
Pinellas County
Manatee County
FL
none
NOT TO BE USED FOR NAVIGATION
Dean Gesch
U.S. Geological Survey
mailing and physical address
EROS Data Center
Sioux Falls
SD
57198
USA
605 594-6055
gesch@usgs.gov
The data set is a joint effort between the USGS/EROS, the NOAA/National Ocean Service (NOS)/Coast Survey Development Laboratory, and the USGS Center for Coastal Watershed Studies.
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.1.0.722
For the LiDAR only: The expected accuracy of the measured variables are as follows: attitude within 0.07 degree, 3-cm nominal ranging accuracy, and vertical elevation accuracy of +/- 20 cm (bald earth). Quality checks are built into the data-processing software.
For the LiDAR: Flights were conducted during the winter season when clear, windless, and calm conditions persisted. A visual record of each flight was taken. Not applicable for other sources.
Value coded as "NO DATA" indicates areas where no data exists in the ARC/INFO GRID.
Because the source bathymetric, topographic, and LiDAR data vary in density and accuracy, users need to be made aware of the spatially varying quality of the merged model. In some areas, the spacing of the soundings would support gridding at a higher resolution than 1/9-arc second, where in other areas the values of the 1/9-arc-second grid were interpolated based only on distant points.
Current work involves generating spatial indices of data quality and accuracy that are coregistered with the model to help users better judge the applicability of the model for their application in a specific location. One index will be a representation of the density (point spacing) of the input sounding data. This index will be helpful for indicating to users the inherent accuracy of the source data, and thus the derived merged model. Without such labeling, users may assume more accuracy than is actually present, especially because the data are presented in a seamless fashion where discontinuities among data sources have been intentionally minimized
The vertical accuracy of the model varies spatially, due mainly to the wide variety of dates and data collection technologies used for source data acquisition. A merged raster model at a uniform grid cell spacing was produced because most users require such a product for their computer mapping systems. Current work involves generating spatial indices of data quality and accuracy that are coregistered with the model to help users better judge the applicability of the model for their application in a specific location. An index will portray the estimated vertical accuracy of the bathymetric and topographic data. This index will be helpful for indicating to users the inherent accuracy of the source data, and thus the derived merged model. Without such labeling, users may assume more accuracy than is actually present, especially because the data are presented in a seamless fashion where discontinuities among data sources have been intentionally minimized, and the vertical units are expressed to sub-meter precision.
U.S. Geological Survey
Unknown
USGS 7.5-minute DEMs
Reston VA
U.S. Geological Survey
digital file
1949
1995
ground condition
DEMs
land elevation information
National Oceanic and Atmospheric Administration
Unknown
NOAA hydrographic surveys
Silver Spring MD
National Oceanic and Atmospheric Administration
paper
1945
1996
publication date
NOAA
water depth information
USGS Center for Coastal and Watershed Studies
2005
USGS LiDAR
digital file
20040305
20040313
ground condition
LiDAR
Near-shore water depth information
A seamless bathymetric/topographic/LiDAR digital elevation model (DEM) was developed by merging the "best available" topographic and LiDAR data from the USGS and bathymetric data from NOAA. Each of the datasets was initially processed independently to apply the "best available" criteria to select the data to be merged. Prior to merging, the selected data were transformed to a common reference coordinate system, both horizontally and vertically.
The best available bathymetric data were selected with a GIS query procedure that applied spatial and temporal filters to the 47 digital NOAA hydrographic surveys, dating from 1945 to 1996, which cover the Tampa Bay region. Approximately 600,000 soundings were transformed from multiple orthometric and tidal vertical datums to a common vertical reference.
The best available topographic data were selected from the USGS National Elevation Dataset (NED). NED is a seamless raster elevation data set that provides national U.S. coverage at a grid spacing of 1/3-arc-second (approximately 10-meters). NED is derived from source DEM's that have a resolution of either 10-meters or 30-meters. NED production includes the following processing steps performed on the individual source 7.5-minute DEM files: datum and coordinate unit conversion (horizontal and vertical), projection transformation and resampling, filtering (for removal of production artifacts), mosaicing, edge matching, and metadata generation. The resulting data set includes an elevation value (expressed in decimal meters referenced to NAVD88) posted every 1/3-arc-second on a latitude/longitude grid (referenced to the NAD83 horizontal datum).
The data are collected using a Cessna 310 aircraft. The NASA Experimental Advanced Airborne Research Lidar (EAARL) laser scanner collects the data using a green (532nm) raster scanning laser, while a digital camera acquires a visual record of the flight. The data are stored on hard drives and archived at the USGS St. Petersburg office and the NASA Wallops office. The navigational data are processed at Wallops. The navigational and raw data are then downloaded into the Airborne Lidar Processing System (ALPS). Data are converted from units of time to x,y,z points for elevation. The derived surface data can then be converted into raster data (geotiffs).
The Tampa Bay region was extracted from NED. Standard tools and datasets (VERTCON and GEOID99) from the National Geodetic Survey were used to transform the elevation data into the common vertical reference frame. Bathymetric points were not used where LiDAR points were available. The NED "shoreline" (interface of zero/non-zero elevations) was used to make the final selection of bathymetry and topography points for merging. All land elevations within 60 meters of the shoreline were converted from raster format to XYZ point data. All bathymetry points coinciding with areas of zero elevation in NED were selected. Because of the age of some of the hydrographic surveys, some of the soundings were located on areas that had been filled and are now represented as land in the DEM. These points were withheld from further processing.
The selected topography points within the shoreline buffer zone and the bathymetry points were gridded to produce a raster surface model with a cell size of 1/9 arc-second. The NED data were resampled to 1/9 arc-second cell size. The points were input to an implementation of the ANUDEM thin plate spline interpolation algorithm, which is optimized for generation of topographic surfaces. The bathymetry points could have been gridded independently of the topographic data, but the shoreline zone land elevations were included in the interpolation to ensure a better match of the bathymetric and topographic surfaces for the subsequent mosaicing step. To avoid introduction of any interpolation edge effects into the merged elevation model, the output grid from the interpolation was clipped to include only land elevations within 30 meters of the shoreline. The final processing step involved the mosaicing of the bathymetry grid and the NED elevation grid. The values in the 30-meter overlap area were blended by weighted averaging, where the weights for each grid are determined on a cell-by-cell basis according to the cell's proximity to the edges of the overlap area. The resulting final merged product is a seamless bathymetric/topographic/LiDAR model covering the Tampa Bay region at a grid spacing of 1/9-arc-second. The vertical coordinates represent elevation in decimal meters relative to the NAVD88 datum, and the horizontal coordinates are decimal degrees of latitude and longitude referenced to the NAD83 datum.
20060406
Tampa Bay topographic/bathymetric DEM
Dean Gesch
U.S. Geological Survey
mailing and physical address
EROS Data Center
Sioux Falls
SD
57198
USA
605 594-6055
gesch@usgs.gov
Tampa Bay region
Raster
Pixel
24300
16200
1
0.000000
0.000000
Decimal degrees
North American Datum of 1983
Geodetic Reference System 80
6378137.000000
298.257222
North American Vertical Datum of 1988
1.000000
meters
Explicit elevation coordinate included with horizontal coordinates
Customer Services Representative
EROS Data Center
mailing and physical address
U.S. Geological Survey EROS Data Center
Sioux Falls
SD
57198
USA
605-594-6151
605-594-6589
custserv@edcmail.cr.usgs.gov
topographic/bathymetric/LiDAR DEM
Although these data have been processed successfully on a computer system at the U.S. Geological Survey, EROS Data Center, no warranty expressed or implied is made by either regarding the utility of the data on any system, nor shall the act of distribution constitute any such warranty. The USGS will warrant the delivery of this product in computer-readable format and will offer appropriate adjustment of credit when the product is determined unreadable by correctly adjusted computer peripherals, or when the physical medium is delivered in damaged condition. Requests for adjustments of credit must be made within 90 days from the date of this shipment from the ordering site.
ARCG
21.183
http://chartmaker.ncd.noaa.gov/bathytopo
none
20060407
Jo Anne Stapleton
U.S. Geological Survey
mailing address
521 National Center
Reston
VA
20192
USA
703 648 4592
703 648 4614
jastapleton@usgs.gov
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998
local time
http://www.esri.com/metadata/esriprof80.html
ESRI Metadata Profile
http://www.esri.com/metadata/esriprof80.html
ESRI Metadata Profile