To generate the land surface grid for this project, VIEWLOG was used to re-sample a 100-ft digital elevation model (DEM) of best-available data for the Lower West Coast planning region of the SFWMD. The original DEM was composited in 2013 from multiple sources. The 100 x 100 foot cell size of the DEM was resampled to a grid size of 2000 x 2000 feet (Liebermann and Bedell, 2013). The vertical datum is NGVD29. The contour interval is in feet.The objectives of this study were to create regional hydrogeologic maps including contour maps showing unit surfaces and thicknesses, and cross-sections representative of both the surficial aquifer system (SAS) and intermediate aquifer system (IAS). The maps, source data, and metadata used to generate these products will be archived in a manner suitable for model implementation and regulatory use in a publically accessible format. The results will be incorporated into the forthcoming Lower West Coast Surficial Aquifer System and Intermediate Aquifer System Model (LWCSIM), which will evaluate the potential impact of existing and projected groundwater withdrawals in all SAS and IAS aquifers within the region over the next several decades.For full documentation, please see Technical Publication WS-35, "Hydrogeologic Unit Mapping Update for the Lower West Coast Water Supply Planning Area," dated August 2015 by Elizabeth Geddes, Emily Richardson P.G., and Anne Dodd P.G. , Water Supply Bureau, Water Resources Division, South Florida Water Management District, West Palm Beach, Florida.https://www.sfwmd.gov/sites/default/files/documents/ws-35_lwc_hydrogeologic_mapping_083115.pdf

The U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC) conducted research to identify areas of seafloor elevation stability and instability based on elevation changes between the 1930’s and 2002 in the Upper Florida Keys (UFK) from Triumph Reef to Pickles Reef within a 234.2 square-kilometer area. USGS SPCMSC staff used seafloor elevation-change data from Yates and others (2017a) derived from an elevation-change analysis between two elevation datasets acquired in the 1930’s and 2001/2002 using the methods of Yates and others (2017b). Most of the elevation data from the 2001/2002 time period were collected during 2002, so as an abbreviated naming convention, we refer to this time period as 2002. A seafloor stability threshold was determined for the 1930’s-2002 UFK elevation-change dataset based on the vertical uncertainty of the 1930’s historical hydrographic surveys and 2002 digital elevation models (DEMs). Five stability categories (which include, Stable: 0.0 meters (m) to ±0.24 m or 0.0 m to ±0.49 m; Moderately stable: ±0.25 m to ±0.49 m; Moderately unstable: ±0.50 m to ±0.74 m; Mostly unstable: ±0.75 m to ±0.99 m; and Unstable: ±1.00 m to Max/Min elevation change) were created and used to define levels of stability and instability for each elevation-change value (25,982 data points) based on the amount of erosion and accretion during the 1930’s to 2002 time period. Seafloor-stability point and triangulated irregular network (TIN) surface models were created at five different elevation-change data resolutions (1st order through 5th order) with each resolution becoming increasingly more detailed. The stability models were used to determine the level of seafloor stability at potential areas of interest for coral restoration and 13 habitat types found in the UFK. Stability surface (TIN) models were used for areas defined by specific XY geographic points, while stability point models were used for areas defined by bounding box coordinate locations. This data release includes ArcGIS map packages containing the binned and color-coded stability point and surface (TIN) models, potential coral restoration locations, and habitat files; maps of each stability model; and data tables containing stability and elevation-change data for the potential coral restoration locations and habitat types. Data were collected under Florida Keys National Marine Sanctuary permit FKNMS-2016-068.

This dataset was created to represent the land surface elevation at 1:24,000 scale for Florida. The elevation contour lines representing the land surface elevation were digitized from United States Geological survey 1:24,000 (7.5 minute) quadrangles and were compiled by South Florida, South West Florida, St. Johns River and Suwannee River Water Management Districts and FDEP. QA and corrections to the data were supplied by the Florida Department of Environmental Protection's Florida Geological Survey and the Division of Water Resource Management. This data, representing over 1,000 USGS topographic maps, spans a variety of contour intervals including 1 and 2 meter and 5 and 10 foot. The elevation values have been normalized to feet in the final data layer. Attributes for closed topographic depressions were also captured where closed (hautchered) features were identified and the lowest elevation determined using the closest contour line minus one-half the contour interval. This data was derived from the USGS 1:24,000 topographic map series. The data is more than 20 years old and is likely out-of-date in areas of high human activity.

This is a tiled collection of the 3D Elevation Program (3DEP) and is one meter resolution. The 3DEP data holdings serve as the elevation layer of The National Map, and provide foundational elevation information for earth science studies and mapping applications in the United States. Scientists and resource managers use 3DEP data for hydrologic modeling, resource monitoring, mapping and visualization, and many other applications. The elevations in this DEM represent the topographic bare-earth surface. USGS standard one-meter DEMs are produced exclusively from high resolution light detection and ranging (lidar) source data of one-meter or higher resolution. One-meter DEM surfaces are seamless within collection projects, but, not necessarily seamless across projects. The spatial reference used for tiles of the one-meter DEM within the conterminous United States (CONUS) is Universal Transverse Mercator (UTM) in units of meters, and in conformance with the North American Datum of 1983 ...

The U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC) conducted research to identify areas of seafloor elevation stability and instability based on elevation changes between the 1930’s and 2016 along the Florida Reef Tract (FRT) from Miami to Key West within a 982.4 square-kilometer area. USGS SPCMSC staff used seafloor elevation-change data from Yates and others (2021) derived from an elevation-change analysis between two elevation datasets acquired in the 1930’s and 2016/2017 using the methods of Yates and others (2017). Most of the elevation data from the 2016/2017 time period were collected during 2016, so as an abbreviated naming convention, we refer to this time period as 2016. A seafloor stability threshold was determined for the 1930’s-2016 FRT elevation-change dataset based on the vertical uncertainty of the 1930’s historical hydrographic surveys and 2016 digital elevation models (DEMs). Five stability categories (which include, Stabl ...

IMPORTANT IN THE OPEN DATA PORTAL THERE IS ONE FEATURE CLASS FOR ALL POTENTIOMETRIC SURFACE MAPS. IF YOU WANT JUST ONE TIME PERIOD CLICK ON THE TABLE TAB, THEN CLICK ON THE DATE FIELD. IN THE FILTER BOX ON THE RIGHT ENTER THE MAP YOU WANT (MAY 2000, SEPTEMBER 2015, ETC.). WHEN YOU CLICK THE DOWNLOAD DATASET BUTTON SELECT SPREADSHEET OR KML OR SHAPEFILE UNDER THE FILTERED DATASET OPTION. YOU WILL ONLY GET THE FILTERED DATA FROM THIS DOWNLOAD.Contour lines are created for the potentiometric surface of the upper Floridan aquifer from water level data submitted by the water management districts. The points associated with the water level data are added to Geostatistical Analyst and ordinary kriging is used to interpolate water level elevation values between the points. The Geostatistical Analyst layer is then converted to a grid (using GA Layer to grid tool) and then contour lines (using the Contour tool). Post editing is done to smooth the lines and fix areas that are hydrologically incorrect. The rules established for post editing are: 1) rivers intersecting the UFA follow the rule of V’s; 2) potentiometric surface contour line values don’t exceed the topographic digital elevation model (DEM) in unconfined areas; and 3) potentiometric surface contour lines don’t violate valid measured water level data. Errors are usually located where potentiometric highs are adjacent to potentiometric lows (areas where the gradient is high). Expert knowledge or additional information is used to correct the contour lines in these areas. Some additional data may be river stage values in rivers that intersect the Floridan aquifer or land elevation in unconfined areas. Contour lines created prior to May 2012 may be calculated using a different method. The potentiometric surface is only meant to describe water level elevation based on existing data for the time period measured. The contour interval for the statewide map is 10 feet and is not meant to supersede regional (water management district) or local (city) scale potentiometric surface maps.

The U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC) conducted research to identify areas of seafloor elevation stability and instability based on elevation changes between the years of 1938 and 2004 at Looe Key coral reef near Big Pine Key, Florida (FL), within a 19.06 square-kilometer area. USGS SPCMSC staff used seafloor elevation-change data from Yates and others (2017a) derived from an elevation-change analysis between two elevation datasets acquired in 1938 and 2004 using the methods of Yates and others (2017b). A seafloor stability threshold was determined for the 1938-2004 Looe Key elevation-change dataset based on the vertical uncertainty of the 1938 historical hydrographic survey and 2004 digital elevation model (DEM). Five stability categories (which include, Stable: 0.0 meters (m) to ±0.24 m or 0.0 m to ±0.49 m; Moderately stable: ±0.25 m to ±0.49 m; Moderately unstable: ±0.50 m to ±0.74 m; Mostly unstable: ±0.75 m to ±0.99 m; and ...

NOAA's National Centers for Environmental Information (NCEI) is building high-resolution digital elevation models (DEMs) for select U.S. coastal regions. These integrated bathymetric-topographic DEMs are used to support individual coastal States as part of the National Tsunami Hazard Mitigation Program's (NTHMP) efforts to improve community preparedness and hazard mitigation. Bathymetric, topographic, and shoreline data used in DEM compilation are obtained from various sources including: NOAA; the U.S. Geological Survey (USGS); and other federal, state, and local government agencies, academic institutions, and private companies. DEMs are referenced to the vertical datum of NAVD 88 and horizontal datum of World Geodetic System 1984 geographic (WGS 84). Grid spacing for the DEM is 1/3 arc-second (~10 meters).

The U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC) conducted research to identify areas of seafloor elevation stability and instability based on elevation changes between the years of 2017 and 2018 at Crocker Reef near Islamorada, Florida (FL), within a 6.11 square-kilometer area. USGS SPCMSC staff used seafloor elevation-change data from Yates and others (2019) derived from an elevation-change analysis between two elevation datasets acquired in 2017 and 2018 using the methods of Yates and others (2017). A seafloor stability threshold was determined for the 2017-2018 Crocker Reef elevation-change dataset based on the vertical uncertainty of the 2017 and 2018 digital elevation models (DEMs). Five stability categories (which include, Stable: 0.0 meters (m) to ±0.24 m or 0.0 m to ±0.49 m; Moderately stable: ±0.25 m to ±0.49 m; Moderately unstable: ±0.50 m to ±0.74 m; Mostly unstable: ±0.75 m to ±0.99 m; and Unstable: ±1.00 m to Max/Min elevation change) were created and used to define levels of stability and instability for each elevation-change value (1,525,339 data points at 2-m horizontal resolution) based on the amount of erosion and accretion during the 2017 to 2018 time period. Seafloor-stability point and triangulated irregular network (TIN) surface models were created at five different elevation-change data resolutions (1st order through 5th order) with each resolution becoming increasingly more detailed. The stability point models were used to determine the level of seafloor stability at seven habitat types found at Crocker Reef. This data release includes ArcGIS map packages containing the binned and color-coded stability point and surface (TIN) models and habitat files; maps of each stability model; and data tables containing stability and elevation-change data for the habitat types. Data were collected under Florida Keys National Marine Sanctuary permit FKNMS-2016-068.

The AHF system has been deployed in a series of survey campaigns to collect over 60,000 points covering Everglades National Park, Loxahatchee National Wildlife Refuge, Water Conservation Areas 2 and 3, portions of Big Cypress National Preserve, as well as areas along the Lake Okeechobee littoral zone. Since the AHF System is able to penetrate Everglades vegetation and water cover, it has provided an unprecedented regional view of Everglades topographic gradients and sub-water surface structure. These data are now being used to simulate Everglades water flow with higher resolution and greater accuracy, to estimate water depths in real-time for field study planning, and as input for habitat models used to forecast the effects of water level changes on various important species. The elevation data collected through this project also formed the basic input to generate a regional topographic surface that is the basis for the Everglades Depth Estimation Network (EDEN). These high accuracy elevation data are made available to anyone through the South Florida Information Access website (http://sofia.usgs.gov) data exchange pages.

MAP Activity Accomplishment The USGS Airborne Height Finder (AHF) System was used to perform topographic surveys in Water Conservation Area 3A within the extents of the Lone Palm Head and North of Lone Palm Head 7.5-minute topographic map quadrangles as specified in the MAP/COE Interagency Agreement. The AHF system has been used throughout South Florida for elevation data collection because traditional surveying methods are too difficult, too costly, or simply impossible to use in the harsh wetland environment and broadly inaccessible terrain of the Florida Everglades. This is especially true considering the shear size of the hydrodynamic and biological modeling domains. The AHF is a helicopter-based instrument that uses a GPS receiver, a computer, and a mechanized plumb bob to make measurements. These data were post processed to the reference stations that are part of the AHF geodetic control network. For reasons of accuracy, these reference stations are located no more then 15 kilometers from the helicopter during AHF operations. The GPS data were post processed using Ashtech’s PNAV On The Fly (OTF) software to obtain the trajectory of the AHF platform. These results are then processed through an in-house software package that separates the actual survey points and results from the trajectory. The points are manually checked to ensure data accuracy and completeness. Digital elevation models (DEMs) were then generated from the elevation point data. Existing elevation data derived from LiDAR data for this area were replaced with AHF derived DEMs for reasons of vertical accuracy. The DEMs have been posted on the South Florida Information Access (SOFIA) website: http://sofia.usgs.gov/exchange/desmond/desmondelev.html.

These data were created as part of the National Oceanic and Atmospheric Administration Office for Coastal Management's efforts to create an online mapping viewer called the Sea Level Rise and Coastal Flooding Impacts Viewer. It depicts potential sea level rise and its associated impacts on the nation's coastal areas. The purpose of the mapping viewer is to provide coastal managers and scientists with a preliminary look at sea level rise and coastal flooding impacts. The viewer is a screening-level tool that uses nationally consistent data sets and analyses. Data and maps provided can be used at several scales to help gauge trends and prioritize actions for different scenarios. The Sea Level Rise and Coastal Flooding Impacts Viewer may be accessed at: https://coast.noaa.gov/slr. This metadata record describes the Florida Keys digital elevation model (DEM), which is a part of a series of DEMs produced for the National Oceanic and Atmospheric Administration Office for Coastal Management's Sea Level Rise and Coastal Flooding Impacts Viewer described above. This DEM includes the best available lidar known to exist at the time of DEM creation that met project specifications. This DEM includes data for Miami-Dade and Monroe Counties. The DEM was produced from the following lidar data sets: 1. 2015 Miami-Dade County, Florida Lidar 2. 2015 NOAA NGS Topobathy Lidar: Dry Tortugas 3. 2018 - 2019 NOAA NGS Topobathy Lidar Hurricane Irma: Miami to Marquesas Key, FL The DEM is referenced vertically to the North American Vertical Datum of 1988 (NAVD88) with vertical units of meters and horizontally to the North American Datum of 1983 (NAD83). The resolution of the DEM is approximately 3 meters.

XYZ ASCII format high-resolution bathymetry data generated from the 2010 multibeam sonar survey of the West Florida Shelf-The Edges, Gulf of Mexico, Appalachicola, Florida.

This metadata record describes the ortho & lidar mapping of Pasco County, FL. The mapping consists of lidar data collected using a Leica ALS-40 Lidar Sensor, contour generation, and production of natural color orthophotography with a 30-cm GSD using imagery collected with a Leica ADS-40 Aerial Digital Camera.

Original contact information: Contact Name: Steve Dicks Contact Org: Southwest...

One purpose of the USGS National Assessment of Coastal Change Project is to provide accurate representations of pre-storm ground conditions for areas that are designated high-priority because they have dense populations or valuable resources that are at risk from storm waves. Another purpose of the project is to develop a broad geomorphic coastal classification that, with only minor modification, can be applied to most coastal regions in the United States.

A Coastal Classification Map describing local geomorphic features is the first step toward determining the hazard vulnerability of an area. The Coastal Classification Maps of the National Assessment of Coastal Change Project present ground conditions such as beach width, dune elevations, overwash potential, and density of development. In order to complete a hazard vulnerability assessment, that information must be integrated with other information, such as prior storm impacts and beach stability. The Coastal Classification Maps provide much of the basic information for such an assessment and represent a critical component of a storm-impact forecasting capability.

[Summary provided by the USGS.]

A first-surface elevation map (also known as a Digital Elevation Model, or DEM) of a portion of western Florida, post-Hurricane Charley, was produced from remotely sensed, geographically referenced elevation measurements cooperatively by the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA). Elevation measurements were collected over the area using the NASA Experimental Advanced Airborne Research Lidar (EAARL), a pulsed laser ranging system mounted onboard an aircraft to measure ground elevation, vegetation canopy, and coastal topography. The system uses high-frequency laser beams directed at the Earth's surface through an opening in the bottom of the aircraft's fuselage. The laser system records the time difference between emission of the laser beam and the reception of the reflected laser signal in the aircraft. The plane travels over the target area at approximately 50 meters per second at an elevation of approximately 300 meters. The EAARL, developed by NASA at Wallops Flight Facility in Virginia, measures ground elevation with a vertical resolution of +/-15 centimeters. A sampling rate of 3 kilohertz or higher results in an extremely dense spatial elevation dataset. Over 100 kilometers of coastline can be surveyed easily within a 3- to 4-hour mission. When subsequent elevation maps for an area are analyzed, they provide a useful tool to make management decisions regarding land development.

For more information on Lidar science and the Experimental Advanced Airborne Research Lidar (EAARL) system and surveys, see http://ngom.usgs.gov/dsp/overview/index.php and http://ngom.usgs.gov/dsp/tech/eaarl/index.php .

A bare-earth digital elevation map (also known as a Digital Elevation Model, or DEM) of a portion of the eastern Florida coastline was produced from remotely sensed, geographically referenced elevation measurements cooperatively by the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA). Elevation measurements were collected over the area using the NASA Experimental Advanced Airborne Research Lidar (EAARL), a pulsed laser ranging system mounted onboard an aircraft to measure ground elevation, vegetation canopy, and coastal topography. The system uses high-frequency laser beams directed at the Earth's surface through an opening in the bottom of the aircraft's fuselage. The laser system records the time difference between emission of the laser beam and the reception of the reflected laser signal in the aircraft. The plane travels over the target area at approximately 50 meters per second at an elevation of approximately 300 meters. The EAARL, developed by NASA at Wallops Flight Facility in Virginia, measures ground elevation with a vertical resolution of +/-15 centimeters. A sampling rate of 3 kilohertz or higher results in an extremely dense spatial elevation dataset. Over 100 kilometers of coastline can be surveyed easily within a 3- to 4-hour mission. When subsequent elevation maps for an area are analyzed, they provide a useful tool to make management decisions regarding land development.

For more information on Lidar science and the Experimental Advanced Airborne Research Lidar (EAARL) system and surveys, see http://ngom.usgs.gov/dsp/overview/index.php and http://ngom.usgs.gov/dsp/tech/eaarl/index.php .

This topographic map is designed to be used as a basemap and a reference map. The map has been compiled by Esri and the ArcGIS user community from a variety of best available sources. The map is intended to support the ArcGIS Online basemap gallery. For more details on the map, please visit the World Hillshade and World Topographic Map.

This digital elevation model (DEM) is a part of a series of DEMs produced for the National Oceanic and Atmospheric Administration Coastal Services Center's Sea Level Rise and Coastal Flooding Impacts Viewer (www.csc.noaa.gov/slr/viewer). This metadata record describes the DEM for Mobile County in Alabama and Escambia, Santa Rosa, and Okaloosa (southern coastal portion only) Counties in Florida. The DEM includes the best available lidar data known to exist at the time of DEM creation for the coastal areas of Mobile County in Alabama and Escambia, Santa Rosa, and Okaloosa (portion) counties in Florida, that met project specification.This DEM is derived from the USGS National Elevation Dataset (NED), US Army Corps of Engineers (USACE) LiDAR data, as well as LiDAR collected for the Northwest Florida Water Management District (NWFWMD) and the Florida Department of Emergency Management (FDEM). NED and USACE data were used only in Mobile County, AL. NWFWMD or FDEM data were used in all other areas. Hydrographic breaklines used in the creation of the DEM were obtained from FDEM and Southwest Florida Water Management District (SWFWMD). This DEM is hydro flattened such that water elevations are less than or equal to 0 meters.This DEM is referenced vertically to the North American Vertical Datum of 1988 (NAVD88) with vertical units of meters and horizontally to the North American Datum of 1983 (NAD83). The resolution of the DEM is approximately 5 meters. This DEM does not include licensed data (Baldwin County, Alabama) that is unavailable for distribution to the general public. As such, the extent of this DEM is different than that of the DEM used by the NOAA Coastal Services Center in creating the inundation data seen in the Sea Level Rise and Coastal Impacts Viewer (www.csc.noaa.gov/slr/viewer).The NOAA Coastal Services Center has developed high-resolution digital elevation models (DEMs) for use in the Center's Sea Level Rise And Coastal Flooding Impacts internet mapping application. These DEMs serve as source datasets used to derive data to visualize the impacts of inundation resulting from sea level rise along the coastal United States and its territories.The dataset is provided "as is," without warranty to its performance, merchantable state, or fitness for any particular purpose. The entire risk associated with the results and performance of this dataset is assumed by the user. This dataset should be used strictly as a planning reference and not for navigation, permitting, or other legal purposes.

This is the 1st release of the fourth version of an Everglades Depth Estimation Network (EDEN) digital elevation model (DEM) generated from certified airborne height finder (AHF) and airboat collected ground surface elevations for the Greater Everglades Region. Collectively, these data are referred to as "High Accuracy Elevation Data" (HAED). This version differs from the previous elevation model (EDEN_EM_OCT07) in several ways. First, the kriging algorithm applied to newly modeled subareas was changed from ordinary to universal kriging - resulting in slightly lower errors during cross-validation and accuracy assessment. Second, to increase accuracy in Water Conservation Area 1 (WCA1), the most challenging EDEN subarea from an elevation modeling standpoint, the Conservation area is subdivided into 3 zones (North, Central, South). Boundaries between the North, Central and South zones are based upon landscape units defined in the CERP Monitoring and Assessment Plan, Part 1, Figure 3-20 on p. 3-38 (p. 36 in the pdf file)) at http://www.evergladesplan.org/pm/recover/recover_docs/map/MAP_3.1_GE.pdf.

The South landscape unit (representing approximately the southern third of WCA1) was further divided into two zones (east and west, termed "Southeast" and "Southwest") based on marked changes in slope and aspect data generated from a DEM of the South landscape unit as a whole. Division of WCA1 into 4 zones reduces errors estimated by comparing DEM modeled water depths with those measured by EDEN Principal Investigators in the field. Subdivision of the South landscape unit into east and west zones resulted in lower error estimates for the Southeast zone without significantly affecting (i.e., improving or degrading) the quality of the Southwest zone - an area where DEM modeling is most challenging. To reduce artificial breaks in elevation along WCA1 subarea boundaries, models were overlapped by 1 cell at these boundaries and, for the North, Central and South zone boundaries, overlapping model values were averaged. For the boundaries between the Southwest and Southeast zones, cell values were "blended" based on weighted distance from the boundary edge. Finally, points along the North / Central and Central / South zone edges were subjectively selected and changed by adding or subtracting 0.03 meters (3 cm) to particular cells based on nearby cell values. This slightly reduces apparent artifacts without drastically affecting the integrity of the model. The EDEN offers a consistent and documented dataset that can be used to guide large-scale field operations, to integrate hydrologic and ecological responses, and to support biological and ecological assessments that measure ecosystem responses to the Comprehensive Everglades Restoration Plan. To produce historic and near-real time maps of water depths, the EDEN requires a system-wide DEM of the ground surface.

This file is intended specifically for use in the EDEN applications software. Therefore, it is a modification of the eden DEM released in January of 2010 (i.e., eden_em_ja10). The released January 2010 data was modified in two ways. First, elevation values have been converted from meters (m) to centimeters (cm). Second, data have been removed from the southern Big Cypress National Preserve and northwestern Everglades National Park area so that this DEM boundary matches the EDEN boundary still in use in EDEN applications software. Aside from this difference in horizontal units and area of coverage, the following data documentation applies.

A digital elevation map (also known as a Digital Elevation Model, or DEM) of a portion of the eastern Florida coastline was produced from remotely sensed, geographically referenced elevation measurements cooperatively by the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA). Elevation measurements were collected over the area using the NASA Experimental Advanced Airborne Research Lidar (EAARL), a pulsed laser ranging system mounted onboard an aircraft to measure ground elevation, vegetation canopy, and coastal topography. The system uses high-frequency laser beams directed at the Earth's surface through an opening in the bottom of the aircraft's fuselage. The laser system records the time difference between emission of the laser beam and the reception of the reflected laser signal in the aircraft. The plane travels over the target area at approximately 50 meters per second at an elevation of approximately 300 meters. The EAARL, developed by NASA at Wallops Flight Facility in Virginia, measures ground elevation with a vertical resolution of +/-15 centimeters. A sampling rate of 3 kilohertz or higher results in an extremely dense spatial elevation dataset. Over 100 kilometers of coastline can be surveyed easily within a 3- to 4-hour mission. When subsequent elevation maps for an area are analyzed, they provide a useful tool to make management decisions regarding land development. For more information on Lidar science and the Experimental Advanced Airborne Research Lidar (EAARL) system and surveys, see http://ngom.usgs.gov/dsp/overview/index.php and http://ngom.usgs.gov/dsp/tech/eaarl/index.php .