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2006 Maryland Department of Natural Resources Lidar: Caroline, Kent and Queen Anne Counties

Maryland Department of Natural Resources requested the collection of LIDAR data over Kent, Queen Anne and Caroline Counties, MD. In response, EarthData acquired the data from March 18 through April 6, 2006. Airborne lidar data was acquired at an altitude of 5,500'(1676.4 m) above mean terrain with a swath width of 40', which yields an average post spacing of lidar points of no greater than 6.56 ft (2 m). The project was designed to achieve a vertical accuracy of the lidar points at 7.09 in (18 cm) root mean square error (RMSE). The flight design included a total of seventy-seven flight lines with approximately 2,246 total line miles (3614.59 km). The lidar data was acquired prior to the emergence of deciduous foliage. This is a bare earth data set. Light Detection and Ranging (LIDAR) is a method of locating objects on the ground using aerial-borne equipment. It is similar to RADAR or SONAR in that the two-way travel time of an energy beam reflected off an object is precisely measured, but this technology uses laser light instead of radio or sound waves. This technology has proven very useful in remote sensing of the earth. It can be used for determining elevations of both the earth's surface and items (natural and man-made) on the surface. Analysis of LiDAR data is used in detailed modeling of the earth's surface for drainage and floodplain studies, determining how a new structure will affect views from various locations, shoreline erosion studies, and other reasons. "First returns" are the first elevation value that the LiDAR sensor recorded for a given x,y coordinate. Likewise, "last returns" are the last elevation value that the LiDAR sensor recorded for a given x,y coordinate. The Bare Earth Mass Points are point elevations that represent the "bare earth." Features that are above the ground - such as buildings, bridges, tree tops, etc. - are not included in these data. The Gridded DEM is a model of the surface of the earth (no above-surface features such as buildings, tree tops, etc) with a point at every 2 meters representing the average surface elevation of that area. The LIDAR Intensity Imagery are similar to aerial photography. While not as sharp as traditional aerial photos, they offer a good visual representation of the surface and various features.
Cite this dataset when used as a source.
Online Access
  • Online access is not available for this resource
Distribution Formats
  • LAZ
Distributor DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
Dataset Point of Contact Kevin Boone
Chief GIS Officer
Maryland Department of Natural Resources
Associated Resources
  • Lidar QA/QC Report
  • publication: 2006-10-05
Data Presentation Form: Digital image
Dataset Progress Status Complete
Data Update Frequency: Unknown
Purpose: The LIDAR-derived data were collected by the Maryland Department of Natural Resources in support of shore erosion studies along the shorelines of the Chesapeake Bay. It also supports the Federal Emergency Management Agency's specifications for mapping floodplains. These efforts required detailed elevation data and models, such as those available from LIDAR sensing. The data have also been made available to aid in other projects that require detailed surface, vegetation and/or structure elevations.
Use Limitations
  • These data depict the elevations at the time of the survey and are only accurate for that time. Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations. Any conclusions drawn from analysis of this information are not the responsibility of NOAA or any of its partners. These data are NOT to be used for navigational purposes.
  • DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
  • Maryland Department of Natural Resources
  • DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
Time Period: 2006-03-18 to 2006-04-06
Spatial Reference System: urn:ogc:def:crs:EPSG::4269 Ellipsoid in Meters
Spatial Bounding Box Coordinates:
N: 39.383359
S: 38.729653
E: -75.688478
W: -75.300698
Spatial Coverage Map:
Theme keywords
  • Bathymetry/Topography
  • Lidar
  • DEM
  • Topographic
  • Bare earth
  • Intensity image
  • LAS
Place keywords
  • US
  • Maryland
  • Caroline County
  • Kent County
  • Queen Anne County
  • Chesapeake Bay
Use Constraints No constraint information available
Fees Fee information not available.
Lineage information for: dataset
  • EarthData International
  • EarthData International
  • DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
Processing Steps
  • 2006-10-05T00:00:00 - EarthData has developed a unique method for processing lidar data to identify and remove elevation points falling on vegetation, buildings, and other aboveground structures. The algorithms for filtering data were utilized within EarthData's proprietary software and commercial software written by TerraSolid. This software suite of tools provides efficient processing for small to large-scale, projects and has been incorporated into ISO 9001 compliant production work flows. The following is a step-by-step breakdown of the process: 1. Using the lidar data set provided by EarthData, the technician performs calibrations on the data set. 2. Using the lidar data set provided by EarthData, the technician performed a visual inspection of the data to verify that the flight lines overlap correctly. The technician also verified that there were no voids, and that the data covered the project limits. The technician then selected a series of areas from the data set and inspected them where adjacent flight lines overlapped. These overlapping areas were merged and a process which utilizes 3-D Analyst and EarthData's proprietary software was run to detect and color code the differences in elevation values and profiles. The technician reviewed these plots and located the areas that contained systematic errors or distortions that were introduced by the lidar sensor. 3. Systematic distortions highlighted in step 2 were removed and the data was re-inspected. Corrections and adjustments can involve the application of angular deflection or compensation for curvature of the ground surface that can be introduced by crossing from one type of land cover to another. 4. The lidar data for each flight line was trimmed in batch for the removal of the overlap areas between flight lines. The data was checked against a control network to ensure that vertical requirements were maintained. Conversion to the client-specified datum and projections were then completed. The lidar flight line data sets were then segmented into adjoining tiles for batch processing and data management. 5. The initial batch-processing run removed 95% of points falling on vegetation. The algorithm also removed the points that fell on the edge of hard features such as structures, elevated roadways and bridges. 6. The operator interactively processed the data using lidar editing tools. During this final phase the operator generated a TIN based on a desired thematic layers to evaluate the automated classification performed in step 5. This allowed the operator to quickly re-classify points from one layer to another and recreate the TIN surface to see the effects of edits. Geo-referenced images were toggled on or off to aid the operator in identifying problem areas. The data was also examined with an automated profiling tool to aid the operator in the reclassification. 7. The final DEM was written to an LAS 1.0 format and also converted to ASCII 8. The point cloud data were also delivered in LAS 1.0 format and also converted to ASCII.
  • 2006-11-20T00:00:00 - EarthData utilizes a combination of proprietary and COTS processes to generate intensity images from the lidar data. Intensity images are generated from the full points cloud (minus noise points) and the pixel width is typically matched to the post spacing of the lidar data to achieve the best resolution. The following steps are used to produce the intensity: 1) Lidar point cloud is tiled to the deliverable tile layout. 2) All noise points, spikes, and wells are deleted out of the tiles. 3) An EarthData proprietary piece of software, EEBN2TIF is then used to process out the intensity values of the lidar. At this point, the pixel size is selected based on best fit or to match the client specification if noted in the SOW. 4) The software then generates TIF and .TFW files for each tile. 5) ArcView is used to review and QC the tiles before delivery.
  • 2008-11-03T00:00:00 - The NOAA Coastal Services Center (CSC) received the files in las and ASCII format. The data were in Maryland State Plane Projection, NAVD88 vertical datum and the vertical units of measure were meters. CSC performed the following processing to the las data to make it available within Digital Coast: 1. The data were converted from Maryland State Plane coordinates to geographic coordinates. 2. The data were converted from NAVD88 (orthometric) heights to GRS80 (ellipsoid) heights using Geoid 03. 3. The LAS data were sorted by latitude and the headers were updated.
  • 2009-07-23T00:00:00 - 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 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 ( 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 heights.
Source Datasets
  • Report of Survey for Caroline, Kent & Queen Anne's Counties
    • Description of Source: Source Contribution: Ground Control. Earthdata International was contracted to provide LIDAR mapping services in the area of Caroline, Kent, and Queen Anne's Counties, Maryland. Earthdata subcontracted the ground survey tasks to TerraSurv, Inc. The Global Positioning System (GPS) was used to establish the control network. The horizontal datum was the North American Datum of 1983, CORS adjustment (NAD 1983 CORS). The vertical datum was the North American Vertical Datum of 1988(NAVD 1988). There were a total of 27 stations occupied for this project. There were 19 new LIDAR control stations, 2 temporary GPS base stations, 3 existing NSRS control stations, 2 CORS stations, and 1 airborne GPS base station used by the flight crew. The network was observed in a radial configuration. A base receiver was established on a random point and run throughout the observations in each area. Due to the large area covered, multiple base locations were used. The temporary base stations were tied to the CORS and NSRS control stations. Source Type: Electronic mail system
    • Temporal extent used: Unknown to
  • Aerial Acquisition of Lidar Data for Kent, Queen Anne & Caroline Counties, MD
    • Description of Source: Source Contribution: Aerial Lidar Acquisition. Maryland Department of Natural Resources requested the collection of LIDAR data over Kent, Queen Anne and Caroline Counties, MD. In response EarthData acquired the data from March 18 through April 6, 2006 using its aircraft with tail number N62912. LIDAR data was captured using an ALS50 LIDAR system, including an inertial measuring unit (IMU) and a dual frequency GPS receiver. An additional GPS receiver was in constant operation over a published control point set by EarthData at the base of operations airport which is a secondary Airport Control Station. During the data acquisition, the receivers collected phase data at an epoch rate of 1 Hz. The use of the Airport base station ensured that all data capture was performed within 50 miles of a base station. The solutions from Kent, Queen Anne and Caroline counties were found to be of high integrity and met the accuracy requirements for the project. These accuracy checks also verified that the data meets the guidelines outlined in FEMA's Guidelines and Specifications for Flood Hazard Mapping Partners and Appendix 4B, Airborne Light Detection and Ranging Systems. Airspeed - 140 knots Laser Pulse Rate - 52700 kHz Field of View - 40 degrees ScanRate - 30 Hz Source Type: Firewire Drive
    • Temporal extent used: 2006-03-18 to 2006-04-06
Last Modified: 2013-06-11
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