2020 Maryland Lidar DEM: Anne Arundel County, MD

Original Product: These are Digital Elevation Model (DEM) data as part of the required deliverables for the lidar project. Class 2 (Ground) lidar points in conjunction with the hydro breaklines were used to create a 1 foot hydro-flattened Raster DEM.

Original Dataset Geographic Extent: Anne Arundel county, Maryland, covering approximately 459 square miles.

Original Dataset Description: The lidar project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.35 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 2.1. The data was developed based on a horizontal projection/datum of NAD83 (HARN), State Plane, Feet and vertical datum of NAVD88 (GEOID12B), Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 619 individual 6000 ft x 4000 ft tiles, as tiled intensity rasters, and as tiled bare-earth DEMs; all tiled to the same 6000 ft x 4000 ft schema.

Original Dataset Ground Conditions: Lidar was collected in late 2020, while no snow was on the ground and rivers were at or below normal levels. In order to post process the lidar data to meet task order specifications and meet ASPRS vertical accuracy guidelines, Sanborn Map Company, Inc., utilized a total of 10 ground control points that were used to calibrate the lidar to known ground locations established throughout the project area. An additional 50 independent accuracy check points, 30 in Bare Earth and Urban landcovers (30 NVA points), 20 in Tall Grass and Brushland/Low Trees categories (20 VVA points), were used to assess the vertical accuracy of the data. These check points were not used to calibrate or post process the data.

This metadata record supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV). The 2020 Anne Arundel County, Maryland digital elevation model (DEM) was downloaded from the Maryland iMAP site and the data were processed to be made available for bulk and custom download from the DAV.

To acquire detailed surface elevation data for use in conservation planning, design, research, floodplain mapping, dam safety assessments and elevation modeling, etc. Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create Intensity Images, Breaklines and Raster DEM. The purpose of these lidar data was to produce high accuracy 3D hydro-flattened Digital Elevation Model (DEM) with a 1 foot cell size. These lidar point cloud data were used to create intensity images, 3D breaklines, and hydro-flattened DEMs as necessary.

Raster File Type = TIFF

Bit Depth/Pixel Type = 32-bit float

Raster Cell Size = 1 Foot

Interpolation or Resampling Technique = Triangulated Irregular Network

Required Vertical Accuracy = 19.6 cm NVA

Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners.

Data is available online for bulk and custom downloads.

None

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.

This data set was produced to meet ASPRS Positional Accuracy Standard for Digital Geospatial Data (2014) for a 10-cm RMSEz Vertical Accuracy Class.

Datasets contain complete coverage of tiles. No points have been removed or excluded. A visual qualitative assessment was performed to ensure data completeness. There are no void areas or missing data. The raw point cloud is of good quality and data passes Non-Vegetated Vertical Accuracy specifications.

Data covers the pilot area specified for this project.

Data is backed up to cloud storage.

Data were collected for the state of Maryland by Sanborn. The data were downloaded by the NOAA Office for Coastal Management (OCM) from the MD iMAP site and processed to make it available for custom download from the NOAA Digital Coast Data Access Viewer (DAV) and for bulk download from S3 AWS.