Sanborn Map Company, Inc. 20251201 vector data Product: 2 Foot contours in Geodatabase format. Geographic Extent: Howard county, Maryland covering approximately 253 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 0.7 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Lidar Base Specification 2024, Revision A. The data was developed based on a horizontal projection/datum of NAD83(2011), Maryland, Feet and vertical datum of NAVD88 (GEOID12B), Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 2 individual 5000 foot x 5000 foot tiles clipped to the DPA, as tiled bare-earth DEMs; tiled to the same 5000 foot x 5000 foot schema. Ground Conditions: Lidar was collected in March 2025, 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 a total of 10 ground control points that were used to calibrate the lidar to known ground locations established throughout the project area. 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 2 foot cell size. These lidar point cloud data were used to create 3D breaklines and hydro-flattened DEMs as necessary. Contour File Type = GDB Contour Elevation Units = Feet Downhill Treatment Applied = Monotonic Type of Hydro Treatment Required = Hydro-flattened 20250311 20250311 ground condition Complete None planned -77.18714311 -76.69572928 39.36955481 39.10279965 1259424.39 1398356.69 620183.88 523167.18 None Model Breaklines Elevation Data Lidar None Maryland Howard 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be aware that temporal changes may have occurred since this dataset was collected and that some parts of these data may no longer represent actual surface conditions.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. Data covers the pilot area specified for this project. Breaklines were collected in all inland ponds and lakes ~2 acres or greater. These features were flat and level water bodies at a single elevation for each vertex along the bank. The entire water surface edge is at or below the immediate surrounding terrain. Breaklines were collected for all streams and rivers ~100' nominal width or wider. These features are flat and level bank to bank, gradient will follow the surrounding terrain and the water surface will be at or below the surrounding terrain. Streams/river channels will break at culvert locations however not at elevated bridge locations. All files are inspected to ensure that they conform to the specified file naming conventions, all files load in their correct geographic position, all files conform to the project specifications for file standard and content. Hydro Flattening Breakline Processing: Class 2 (ground) lidar points were used to create a bare-earth surface model. The surface model was then used to heads-up digitize 2D breaklines of inland streams and rivers with a 100 foot nominal width and Inland Ponds and Lakes of 2 acres or greater surface area. Elevation values were assigned to all Inland Ponds and Lakes, Inland Pond and Lake Islands, Inland Stream and River Islands, using LP360 functionality. Elevation values were assigned to all Inland streams and rivers using LP360 functionality. All ground (Class 2) lidar data inside of the collected inland breaklines were then classified to water (Class 9) using LP360 functionality. A buffer of 2 ft was also used around each hydro-flattened feature. These points were moved from ground (Class 2) to Ignored Ground (Class 20). The breakline files were then translated to ESRI File-Geodatabase format using ESRI conversion tools. Breaklines are reviewed against lidar intensity imagery to verify completeness of capture. All breaklines are then compared to TINs (triangular irregular networks) created from ground only points prior to water classification. The horizontal placement of breaklines is compared to terrain features and the breakline elevations are compared to lidar elevations to ensure all breaklines match the lidar within acceptable tolerances. Some deviation is expected between breakline and lidar elevations due to monotonicity, connectivity, and flattening rules that are enforced on the breaklines. Once completeness, horizontal placement, and vertical variance is reviewed, all breaklines are reviewed for topological consistency and data integrity using a combination of ESRI Data Reviewer tools and proprietary tools. 2025 Vector NAD83(2011) / Maryland (ftUS) 38.3 39.45 -77.0 37.6666666666667 1312333.333 0.0 coordinate pair 0.001 0.001 feet NAD 1983 2011 GRS 1980 6378137.0 298.257222101 North American Vertical Datum of 1988, Geoid12B 0.001 feet Explicit elevation coordinate included with horizontal coordinates 20250721 20250721 Sanborn Map Company, Inc. mailing and physical

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Colorado Springs CO 80919 USA (866)726-2676 FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 None. None. None. Unclassified. None. None. None.