Sanborn Map Company, Inc. 20240201 Lidar point cloud Product: These lidar data are processed LAS 1.4 files, formatted to 36 individual LAS files. Geographic Extent: Anne Arundel county, Maryland; covering approximately 459 square miles. 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. The data was developed based on a horizontal projection/datum of NAD83 HARN, Maryland Feet, and vertical datum of NAVD88 (GEOID12B) Feet. Lidar data was delivered as flightline-extent unclassified LAS swaths and as processed Classified LAS 1.4 files, formatted to 619 individual tiles as tiled bare-earth DEMs; tiled to the 4000 ft x 6000 ft schema. Ground Conditions: Lidar was collected in March 2023, 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. established 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). These were used to assess the vertical accuracy of the data. 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 ft cell size. These lidar point cloud data were used to create intensity images, 3D breaklines, and hydro-flattened DEMs as necessary. Sanborn Map Company, Inc. U.S. Geological Survey (USGS) - National Geospatial Program (NGP) Lidar Base Specification Leica TerrainMapper 15 0.34 8.8 0.29 12.1 2000 150 40 150 1800 4 0.47 1064 1 0.25 1456 20 National Geodetic Survey (NGS) Geoid12B 0.5 0 0 1.4 6 Withheld (ignore) points were not identified in these files using the standard LAS Withheld bit. Swath "overage" points were not identified in these files using the standard LAS overlap bit. 11 0 Created, never classified 20230316 20230319 ground condition Complete None planned -76.84152377 -76.39126807 39.23869669 38.71116818 1357552.87 1484753.39 572560.41 380962.83 None Model LAS Point Cloud Remote Sensing Elevation Data Lidar None Maryland Anne Arundel County No restrictions apply to these data. None. However, users should be aware that temporal changes may have occurred since this dataset was collected and that some parts of these data may no longer represent actual surface conditions. Users should not use these data for critical applications without a full awareness of its limitations. Acknowledgement of the U.S. Geological Survey would be appreciated for products derived from these data. Leica HexMap; GeoCue; Windows Data covers the DPA specified for this project. These LAS data files include all data points collected. No points have been removed or excluded. A visual qualitative assessment was performed to ensure data completeness. No void areas or missing data exist. The raw point cloud is of good quality and data passes Non-Vegetated Vertical Accuracy specifications. This data set was tested to meet ASPRS Positional Accuracy Standard for Digital Geospatial Data (2014) for a 10cm RMSEz Vertical Accuracy Class. Actual NVA accuracy was found to be RMSEz = 5.67 cm, equating to +/- 11.03 cm at 95% confidence level. The boresight was completed prior to project execution. The following steps describe the Raw Data Processing process: 1) Technicians processed the raw data to LAS format flight lines using the final GNSS/IMU solution. This LAS data set was used as source data for lidar matching. 2) Technicians utilized commercial and proprietary software packages to analyze how well flight line overlaps match for the entire lift and adjusted as necessary until the results met the project specifications. 3) Once all lifts were completed with lidar matching, the technicians checked and corrected the vertical misalignment of all flight lines and also the matching between data and ground truth. The relative accuracy was less than or equal to 6 cm RMSEz within individual swaths and less than or equal to 8 cm RMSEz or within swath overlap (between adjacent swaths). 4) The technicians ran a final vertical accuracy check of the flight lines against the surveyed check points after the z correction to ensure the requirement of NVA = 19.6 cm 95% Confidence Level (Required Accuracy) was met. Point classification was performed according to USGS Lidar Base Specification, and breaklines were collected for water features. Bare-earth DEMs were exported from the classified point cloud using collected breaklines for hydroflattening. 20231166_Anne_Arundel_MD_Survey 2023 Data was tested at 0.29 meter aggregate nominal pulse spacing and at 12.1 aggregate points per meter. The aggregate nominal pulse spacing was tested on classified tiled LAS using geometrically reliable first-return points. ANPS was tested using Delaunay Triangulation that produced average point spacing between all nearest neighbors. 2023 Point Point 17,701,312,790 NAD 1983 HARN StatePlane Maryland FIPS 1900 Feet 38.3 39.45 -77.0 37.66666666666666 1312333.333333333 0.0 coordinate pair 0.001 0.001 feet North American 1983 HARN GRS 1980 6378137.0 298.257222101 North American Vertical Datum of 1988, Geoid12B 0.001 feet Explicit elevation coordinate included with horizontal coordinates 20240201 20240201 Sanborn Map Company, Inc. mailing and physical

1935 Jamboree Drive, Suite 100

Colorado Springs CO 80920 USA (866)726-2676 FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 None. None. None. Unclassified. None. None. None.