New York Office of Information Technology Services 20251210 Lidar point cloud Product: These lidar data are classified LAS 1.4 files Tiles, formatted to 1873 individual LAS files. Geographic Extent: Long Island, New York, covering approximately 1,627 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 Base Lidar Specification v2024, Rev. A. The data was developed based on a horizontal projection/datum of NAD83 (2011), Universal Transverse Mercator Zone 18N, meters and vertical datum of NAVD88 (GEOID18), meters. Lidar data was delivered as flightline-extent unclassified LAS swaths, and as processed Classified LAS 1.4 files, formatted to 1,873 individual 1500 m x 1500 m tiles, as tiled bare-earth DEMs; all tiled to the same 1500 m x 1500 m schema. Ground Conditions: Lidar was collected in early 2024, 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 31 ground control points that were used to calibrate the lidar to known ground locations established throughout the project area. An additional 102 independent accuracy checkpoints, 72 in Bare Earth and Urban landcovers (72 NVA points), 30 in Tall Grass and Brushland/Low Trees categories (30 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. 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 meter cell size. These lidar point cloud data were used to create 3D breaklines, and hydro-flattened DEMs as necessary. CONTRACTOR: New York Office of Information Technology Services. SUBCONTRACTOR: Sanborn Map Company, Inc. Lidar data were acquired and calibrated by Sanborn Map Company, Inc. All follow-on processing was completed by the prime contractor. U.S. Geological Survey (USGS) - National Geospatial Program (NGP) Lidar Base Specification v2023, Rev. A Leica TerrainMapper 15 0.67 2.2 0.67 2.2 3350 160 40 86.3 720 4 0.78 1064 1 0.25 2438 20 National Geodetic Survey (NGS) Geoid18 0.5 0.0 0 1.4 6 Withheld (ignore) points were 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. 16 0 Created, never classified 20240324 20240416 ground condition Complete None planned -73.78329791 -71.83437964 41.34691317 40.52740079 603000 765000 4578000 4491000 None Model LAS Point Cloud Remote Sensing Elevation Data Lidar None New York Nassau County Queens County Suffolk 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 the limitations of the data. Acknowledgement of New York Office of Information Technology Services would be appreciated for products derived from these data. The data represented is the result of data collection and processing per contract specifications and indicates the general existing conditions at the time of the data collection. As such, it is only valid for its intended use, content, time, and accuracy specifications. The user is responsible for the results of any application of the data for other than its intended purpose. HxMap 4.4; GeoCue v2020.1.22.2; Windows 10 Operating System Data covers the entire area 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. Data voids may be present where surface is of low near infrared reflectivity, such as asphalt or composition roofing. These data dropouts were observed on building rooftops in the project area. The raw point cloud is of good quality and data passes Non-vegetated Vertical Accuracy specifications. This dataset was produced to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 15cm RMSEx / RMSEy Horizontal Accuracy Class which equates to Positional Horizontal Accuract = +/- 29cm at a 95% confidence level. This data set was produced 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 = __cm, equating to +/- __cm at 95% confidence level. Actual VVA accuracy was found to be +/- __cm at the 95th percentile. 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. 20231229_NYSDEP_2024_Survey 2025 Data was tested at 0.67 meter nominal pulse spacing and at 2.2 points per meter. The nominal pulse spacing was tested on raw LAS using geometrically reliable first-return points. NPS was tested using Delaunay Triangulation that produced average point spacing between all nearest neighbors. 20251210 Maximum Surface Height Rasters were produced as ancillary data from the classified lidar point cloud in order to evaluate the withheld bit flag proof of performance for points that cannot be reasonably interpreted as valid surface returns. These were produced using all returns, withheld flagged points excluded, and using the highest elevation point value from each pixel. These rasters are 32-bit, floating point format and delivered as GeoTIFF files per tile. Cell size of the MSHR is 2 meter. MSHR are generated from the point cloud data and will not be altered after creation nor will there be further maintenance on this product. 2025 Swath Separation Imagery was produced for the entire project area. Swath separation images use color-coding to illustrate differences in elevation (z-) values where swaths overlap. The color-coded images are semi-transparent and overlay the lidar intensity image. They are ancillary data used as visual aids to more easily identify regions within point cloud datasets that may have suspect interswath alignment or other geometric issues. Imagery was created using last returns with all classification and bit flags, except for noise and withheld bit flag are included. Images are derived from a TIN and have a 50% transparent RGB layer over lidar intensity. Color intervals are as follows for QL2 data: 0-8cm, green; 8-16cm, yellow; >16cm, red. These files were produced as GeoTIFF tiles using a cell size of 2 meter. SSI are generated from the point cloud data and will not be altered after creation nor will there be further maintenance on this product. 2025 Point Point 12,586,116,786 Universal Transverse Mercator 18 0.9996 -75.0 0.0 500000 0.0 coordinate pair 0.001 0.001 meters North American Datum of 1983 (2011) Geodetic Reference System 80 6378137 298.257222101 North American Vertical Datum of 1988, Geoid 18 0.001 meters Explicit elevation coordinate included with horizontal coordinates 20251210 20251210 New York Office of Information Technology Services mailing and physical

W. Averell Harriman State Office Campus

1220 Washington Avenue, Bldg. 5 - Floor 1

Albany NY 12226 USA (518) 242-5037 FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 None. None. None. Unclassified. None. None. None.