State of Connecticut 2016 1.0 point digital data Connecticut Capitol Region Council of Governments http://crcog.org This metadata record describes the Raw Point Cloud (RPC) for the 2016 Connecticut LiDAR project covering approximately 935 square miles, in which its extents cover Block 2. USGS Base Specification 1.2, QL2 meeting 19.6cm VVA Leica ALS70 4 0.67 2.2 0.67 2.2 2180 140 40 51.3 251 10 0.49 1064 1 0.3 1587 30 NAD_1983_2011_StatePlane_Connecticut_FIPS_0600_Ft_US NGS Geoid12b 0 0.138 181 0.125 181 0.170 95 1.4 6 Withheld points were identified in these files with the withheld flag Overlap points were identified in these files with the overlap flag 16 1 Unclassified 2 Bare earth 7 Noise 9 Water 10 Ignored Ground Breakline Proximity 17 Bridges 18 High Noise To acquire detailed surface elevation data for use in conservation planning, design, research, floodplain mapping, dam safety assessments, and hydrologic modeling. LAS data products are suitable for 1 foot contour generation. USGS LiDAR Base Specification 1.2, QL2. 19.6 cm NVA. Project Projection, Datums and Units. Projection - State Plane Connecticut. Horizontal datum - North American Datum of 1983 (NAD83 (2011)). Vertical datum - North American Vertical Datum of 1988 (NAVD88) using the latest geoid (Geoid12b) for converting ellipsoidal heights to orthometric heights. Units - US feet Notes: -The Scan Direction Flag was lost due to software malfunction. This does not impact the data usability. -The GeoTIFF CRS tags within the Raw Point Cloud are to be ignored, and be superseded by the WKT. Global Encoding bit for WKT use has been set. 20160319 20160413 ground condition Complete Unknown -72.696668 -71.783792 41.568169 41.197396 CT LiDAR mapping point cloud Unclassified points ALS70 Intensity return LAS First Return CT Connecticut Block 2 United States none 2016 This data may be used by the requested party for stated purposes and may be re-distributed. This data is for planning purposes only and should not be used for legal or cadastral purposes. Any conclusions drawn from analysis of this information are not the responsibility of Sanborn Map Company. Users should be aware that temporal changes may have occurred since this dataset was collected and some parts of this dataset may no longer represent actual surface conditions. Users should not use these data for critical applications without a full awareness of its limitations. Contact: State of Connecticut Erik D. Snowden Capitol Region Council of Governments IT/GIS Coordinator mailing address

241 Main Street

10th Floor Romney

Hartford CT 06106 U.S.A. 860.522.2217 x217 860.724.1274 esnowden@crcog.org 8:00 AM - 5:00 PM unknown Unclassified unknown Microsoft Windows 7; ESRI ArcCatalog 9.3.1.1850 State of Connecticut: The LiDAR surface was evaluated using a collection of 181 GPS surveyed checkpoints for the raw NVA report. The DEM was compared to these checkpoints yielding a better result than was required for the project. Raw NVA Control Accuracy Report (US feet) --------- Report Disclaimer --------- This report does not guarantee accuracy. The report only reflects one statistical representation of the control points, LIDAR data and surface used. This report does not replace a thorough quality control process. --------- Report Summary --------- Average dz 0.004 Minimum dz -0.829 Maximum dz 0.622 Average magnitude 0.170 Root mean square 0.227 Std deviation 0.228 ---------------------------------------------------------------------------------------- LiDAR data is collected within the project area and processed. Before the DEMs were created, the dataset was verified against control. Well-distributed control was collected for the entire state of Connecticut. Accuracy is reported for the state as a whole. LiDAR data is collected for the project area. Post processing of the simultaneously acquired GPS/INS is performed and applied to the laser returns to output a point cloud in the specified project coordinate system and datums. The point cloud data is then subjected to automated classification routines to assign all points in the point cloud to ground, water, overlap and unclassified point classes. Anomalous laser returns that occur infrequently are removed entirely from the data set. Horizontal positional accuracy for the Connecticut LiDAR is dependent upon the quality of the GPS/INS solution, sensor calibration and ground conditions at the time of data capture. The data set was produced to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 1.0 meter RMSEx/RMSEy. 1.0 For Connecticut, this value is computed by comparing ground control to a DEM derived from the classified LiDAR data and represents the RMSE of residuals on controls within the project area. For the Raw Point Cloud, the NVA was computed. The vertical accuracy was tested with independent survey check points located in flat terrain types within Connecticut These check points were not used in the calibration or post processing of the lidar point cloud data. The survey check points were distributed throughout the block area. Specifications for this project require that the NVA be 19.6 cm or better @ 95 percent confidence level. 0.138 The raw NVA was tested using 181 independent survey check points located in flat terrain types within the state of Connecticut The survey checkpoints were distributed throughout the block area. The 181 independent check points were surveyed using static GPS base stations collecting point location for 20 minute intervals. Elevations were measured for the x,y,z location of each check point. Elevations interpolated from the DEM surface were then compared to the elevation values of the surveyed control. This data set was tested to meet ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) for a 10cm RMSEz Vertical Accuracy Class. Actual NVA accuracy was found to be RMSEz = 7cm, equating to +/- 13.8cm at 95% confidence level. Sanborn Map Company Inc. Unpublished Material 1.0 Remote sensing image None None disc 2016 ground condition LIDAR and GPS_RAW Aerial LiDAR and GPS/IMU data are recorded for the defined project area at an altitude, flight speed, scanner swath width and scanner pulse frequency to achieve the design goals of the project. Sanborn Map Company Inc. 2010 1.0 tabular digital data None None disc 2016 Ground condition CONT Targeted ground control is used to create a digital control file and control report as well as QC check of LiDAR accuracy. Predefined points (NGS when available) within the project area are targeted. Sanborn Map Company Inc. Unpublished material 1.0 Tabular digital data 1200 disk 2016 Ground condition GPS Post processed GPS/INS is applied to the lidar point data to georeference each point in the project coordinate system Sanborn Map Company Inc. Unpublished material 1.0 Point digital data 1200 Disk 2016 ground condition LAS The post processed lidar data has been projected and oriented in the specified coordinate system as an un-classified point cloud. At selected locations throughout the site, accurate GPS coordinates and elevations are surveyed and the points are marked with targets. None 2016 CONT New LiDAR data is captured for the project area using a Leica ALS70 w/MPiA LiDAR instrument an integrated IPAS20 GPS/INS system mounted within a Aero Commander twin engine airplane. None 2016 LIDAR, GPS_RAW The airborne GPS data is post-processed in Intertial Explorer software and LEICA CloudPro software to determine the LiDAR sensor's angle and orientation in the terrain (project) coordinate system and datums during the survey. GPS_RAW 2016 GPS_SOL The post processed GPS/INS solution is applied to the raw lidar data to orient and project the data points into the project area reference system as an unclassified point cloud. LIDAR, GPS_SOL 2016 LAS The georeferenced lidar data is then classified and edited in Terrasolid Terrascan software. Data is classified to produce: Class 0: Created; Never classified CONT, GPS_SOL, LIDAR 2016 LAS Point State Plane Coordinate System 1983 0600 41.2 41.8666666666667 -72.75 40.8333333333333 999999.999996 499999.999998 coordinate pair 0.01 0.01 survey feet North American Datum of 1983 (2011) Geodetic Reference System 80 6378137.000000 298.257222101004 North American Vertical Datum of 1988(GEOID12b) 0.1 feet Explicit elevation coordinate included with horizontal coordinates Classes: 0- Created; Never classified USGS Base Specification 1.2, QL2 meeting 19.6 cm NVA Erik D. Snowden IT/GIS Coordinator Manager, Geodata Services Section mailing address

241 Main Street

10th Floor Romney

Hartford CT 06106 U.S.A. 860.522.2217 x217 860.724.1274 esnowden@crcog.org 8:00 AM - 5:00 PM Connecticut 2016 LiDAR project The Capitol Region Council of Governments digital data have been tested and their documentation carefully reviewed. However, the Capitol Region Council of Governments and its representatives make no warranty or representation, either expressed or implied, with respect to the digital data and their documentation, their quality, performance, merchantability, or fitness for a particular purpose. The digital data are distributed on "as is" basis, and the user assumes all risk to their quality, the results obtained from their use, and the performance of the data. In no event will the Capitol Region Council of Governments or its representatives be liable for any direct, indirect, special, incidental or consequential damages resulting from and defect in the State of Connecticut or in their documentation. This disclaimer of warranty is exclusive and in lieu of all others, oral or written, express or implied. No agent or employee is authorized to make any modification, extension, or addition to this warranty. LAS 1.4 7000 crcog.org unknown 5 - 1/2 inch hard drive LAS unknown State of Connecticut unknown 2016 2016 Shawn Benham Sanborn Map Co Project Manager mailing address

1935 Jamboree Dr

Colorado Springs CO 80920 U.S.A. 719.502.1296 sbenham@sanborn.com 8:00 AM - 5:00 PM FGDC CSDGM FGDC-STD-001-1998