Northrop Grumman, Advanced GEOINT Solutions Operating Unit20140620Seneca NY Watershed LiDAR DEM Tilesraster digital dataHuntsville, ALNorthrop Grumman, Advanced GEOINT Solutions Operating UnitNorthrop Grumman, Advanced GEOINT Solutions Operating Unit20140620UnknownUSGS Seneca NY Watershed LiDARraster digital dataHuntsville, ALNorthrop Grumman, Advanced GEOINT Solutions Operating UnitThe Light Detection and Ranging (LiDAR) dataset is a survey of the Seneca NY Watershed project area. The entire survey area for Seneca encompasses approximately 1638 square miles. The LiDAR point cloud was flown at a nominal post spacing of 1.5 meters for unobscured areas. The LiDAR data and derivative products produced are in compliance with the U.S. Geological Survey National Geospatial Program LIDAR Base Specifications, Version 1.0. The flight lines were acquired by Northrop Grumman Corporation and Digital Aerial Solutions (DAS) and the data was post processed by Northrop GrummanAdvanced GEOINT Solutions Operating Unit (AGSOU), which was flown over twelve missions from May 5,2012-May 6,2012, November 19,2013-November 21,2013, April 17,2014-April 24,2014, June 15,2014. Derivative products from the aerial acquisition include: raw point cloud data in LAS v1.2 format, classified point cloud data in LAS v1.2 format, bare earth surface (raster DEM) tiles in 32-bit floating point raster ERDAS .IMG format, breaklines in ESRI Arc Shape format, control points in ESRI Arc Shape format, project report, and FGDC compliant XML metadata.The purpose of this project was to produce a high resolution LiDAR data set to assist in change detection mapping of the Seneca NY Watershed located in Central New York2012050520120506201311192013112020140417201404182014042420140615ground conditionUnknown-78.517741528-75.28532527843.28949772242.084474250Digital Elevation ModelElevationSite LocationSeneca NY WatershedStateNew YorkCountryUnited StatesnoneNorthrop Grumman, Advanced GEOINT Solutions Operating UnitSeasonWinter/SpringWayne, Fulton, Onondaga, Seneca, Livingston, Yates, Steuben, Tioga, Schuyler, and TompkinsCountiesYear2012-2014NoneThe data depicts the elevations at time of survey and are accurate only for that time. Exercise professional judgement in using this data.Northrop Grumman, Advanced GEOINT Solutions Operating UnitSean O'BrienProject Managermailing and physical address
301 Voyager Way
HuntsvilleAL35806USA(618) 622-8425sean.m.obrien@ngc.com8:00 - 5:00Northrop Grumman, Advanced GEOINT Solutions Operating UnitUnclassifiedUnclassifiedInformation UnclassifiedMicrosoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 10.1 Service Pack 1The GPS survey was tied into the NYSNet Real Time Network located in New York. The NYSNet network is a network of continuously operating GPS reference stations that provides Real Time Kinematic (RTK) capabilities within a Real Time Network (RTN). This allows corrections to be applied to the points as they are being collected, eliminating the need for an adjustment. As a quality control measure several “check-in” points consisting of NSRS published horizontal and vertical control points were used as checks within the NYSNet network. The survey crew checked into these published points daily to validate the consistency of the network. Also to confirm that the project will meet the 5cm local network accuracy at the 95% confidence level. Survey field work was performed on 3.30.2012-4.12.2012 by Northrop Grumman field crews using Trimble 5700 series Global Positioning System with Zephyr Geodetic antenna. Data analysis was accomplished by comparing ground truth checkpoints with LIDAR points from the derived DEM and reported three ways 1. FVA 2. SVA 3. CVA. Additionally the FVA points were assessed against the TIN derived from the LAS LiDAR point cloud controlled and calibrated swath data to ensure they met the required accuracy of 12.5cm RMSEz and 24.5cm at the 95% confidence interval.Ground Truth data was collected of the three major land cover classes present within the study area. 20 points were collected in each of the three vegetation classes that made up 10% of the vegatation present within the AOI. Those classes are bare earth, tall weeds and crops, and forested and fully grown. A pair of points were surveyed using theNYSNet network once completed the total station is used to collect the taller vegetation classes. A total station was used to collect all the shots collected in the taller vegetation class, due to the limited GPS signal when working in and around vegetation canopy.There is not a systematic method of testing when testing horizontal accuracy in LiDAR. However this is tested during calibration of the sensor and is rechecked during the comparing of parallel and perpendicular flight lines. Additionally the horizontal accuracy is checked by collecting building corners during the survey. Lines are then digitized representing the building outline and the differences are measure from each individual survey point to the corner of the building outline. Stats are calculated to ensure horizontal tolerances are met. These measurements resulted in an RMSEr of 1.86 meters and equals a RMSE accuracy of 3.21 meter horizontal accuracy at the 95 % confidence level. Accuracy defined by NSSDA at the 95 % confidence level would be multiplier by 1.7308 times the RMSE.3.21 metersValue represent horizontal accuracy assessment at the 95% confidence interval.The accuracy assessment was performed using the NSSDA standard method to compute the root mean square error (RMSE) based on a comparison of ground control points (GCP) and DEM derived from the LiDAR dataset. Testing was performed prior to gridding of the filtered LiDAR data points and construction of the 32-bit ESRI float grid format bare earth tiles. The RMSEz figure was used to compute the vertical National Standard for Spatial Data Accuracy (NSSDA). A spatial proximity analysis was used to select edited LiDAR data points contiguous to the relevant GCPs. A search radius decision rule is applied with consideration of terrain complexity, cumulative error and adequate sample size. Cumulative error results from the errors inherent in the various sources of horizontal measurement. These sources include the airborne GPS, GCPs and the uncertainty of the accuracy of the LiDAR data points. This accuracy is achieved prior to the subsampling that occurs through integration with the inertial measurement unit (IMU) positions that are recorded. It is unclear at this time whether the initial accuracy is maintained. The horizontal accuracy of the GCPs is estimated to be in the range of approximately .03 to .04 meters. Finally, sample size was considered. The specification for the National Standard for Spatial Data Accuracy is a minimum of 20 points to conduct a statistically significant accuracy evaluation which provides a reasonable approximation of a normal distribution. The intent of the NSSDA is to reflect the geographic area of interest and the distribution of error in the data set (Federal Geographic Data Committee, 1998, Geospatial National Standard for Spatial Data Accuracy, Federal Geographic Data Committee Secretariat, Reston, Virginia, p.3-4). Additional steps were taken to ensure the vertical accuracy of the LiDAR data including: Step 1: Precision Bore sighting (Check Edge-matching) Step 2: Compare the LiDAR data to the Field Survey (The vertical accuracy requirements meet or exceed the required RMSEz of 12.5cm and the vertical accuracy of 24.5cm at the 95% confidence level). Data collected under this task order exceeds the required National Standards for Spatial Database Accuracy (NSSDA) accuracy standards. SVA accuracies at the 95th Percentile collected and tested, as target accuracies results as follows:Tall Weeds and Crops=0.196 meters, Forested and Fully Grown= 0.319 meters. Consolidated Vertical Accuracies (CVA) at the 95th Percentile =0.236 meters. Final accuracy statement for this task order is as follows; FVA Tested 0.145 meters vertical accuracy at the 95% confidence level.0.145 metersValue represents the Fundamental Vertical Accuracy (FVA) assessment at the 95% confidence interval. This represents the FVA checkpoints compared against the derived DEM at the 95% confidence interval.Northrop Grumman, Advanced GEOINT Solutions Operating Unit20140620UnknownSeneca NY Watershed LiDARraster digital data24000disc20120330unknown20120412unknownground conditionDEMThe USGS Seneca NY Watershed LiDAR Survey was acquired and processed by Northrop Grumman, Advanced GEOINT Solutions Operating Unit for the United States Geological Survey "USGS".The ABGPS, inertial measurement unit (IMU), and raw scans are collected during the LiDAR aerial survey. The ABGPS monitors the xyz position of the sensor and the IMU monitors the orientation. During the aerial survey, laser pulses reflected from features on the ground surface are detected by the receiver optics and collected by the data logger. GPS locations are based on data collected by receivers on the aircraft and base stations on the ground. The ground base stations are placed no more than 40 km radius from the flight survey area.Optech 3100 Airborne LiDAR SensorLeica ALS60 Airborne LiDAR SensorAirborne Global Positioning System20140424LiDAR scan filesLiDAR scans, GPS dataNorthrop Grumman, Advanced GEOINT Solutions Operating UnitSean O'BrienProject Managermailing and physical address
301 Voyager Way
HuntsvilleAL35806USA(618) 622-8425sean.m.obrien@ngc.com8:00 - 5:00Inertial Measuring UnitGlobal Positioning SystemThe ABGPS, IMU, and raw scans are integrated using proprietary software developed by the airborne sensor manufacturer and delivered with each of the two sensors used on this project the Optech System and the Leica System. The resultant file is in a LAS binary file format. The LAS version 1.2 file format can be easily transferred from one file format to another. It is a binary file format that maintains information specific to the LiDAR data (return number, intensity value, xyz, etc.). The resultant points are produced in the NAD83 UTM 18 North Coordinate System, with units in Meters and referenced to the NAVD88 datum. The LiDAR mass points were processed in American Society for Photogrammetry and Remote Sensing LAS 1.2 format. The header file for each dataset is complete as defined by the LAS 1.2 specification. The datasets were divided into a 1500 meter by 1500 meter tiling scheme, named according to the US National Grid scheme. The tiles are contiguous, do not overlap, and are suitable for seamless topographic data mosaics that include no "no data" areas. The names of the tiles include numeric column and row designations and all files utilize the LAS file extensionAirborne Global Positioning System dataInertial Measurement UnitLiDAR scans20140505LiDAR point cloud data sets LAS 1.2 file formatNorthrop Grumman, Advanced GEOINT Solutions Operating UnitSean O'BrienProject Managermailing and physical address
301 Voyager Way
HuntsvilleAL35806USA(618) 622-8425sean.m.obrien@ngc.com8:00 - 5:00The unedited data are classified to facilitate the application of the appropriate feature extraction filters. A combination of proprietary filters are applied as appropriate for the production of bare earth digital elevation models (DEMs). Interactive editing methods are applied to those areas where it is inappropriate or impossible to use the feature extraction filters, based upon the design criteria and/or limitations of the relevant filters. These same feature extraction filters are used to produce elevation height surfaces.LAS 1.2 format20140610Filtered LiDAR data set LAS 1.2 formatNorthrop Grumman, Advanced GEOINT Solutions Operating UnitSean O'BrienProject Managermailing and physical address
301 Voyager Way
HuntsvilleAL35806USA(618) 622-8425sean.m.obrien@ngc.com8:00 - 5:00Filtered and edited data are subjected to rigorous QA/QC, according to the Northrop Grumman, Advanced GEOINT Solutions Operating Unit Quality Control Plan and Procedures. A series of quantitative and visual procedures are employed to validate the accuracy and consistency of the filtered and edited data. Ground control is established by Northrop Grumman, Advanced GEOINT Solutions Operating Unit and GPS-derived ground control points (GCPs) in various areas of dominant and prescribed land cover. These points are coded according to land cover, surface material, and ground control suitability. A suitable number of points are selected for calculation of a statistically significant accuracy assessment, as per the requirements of the National Standard for Spatial Data Accuracy. A spatial proximity analysis is used to select edited LiDAR data points within a specified distance of the relevant GCPs. A search radius decision rule is applied with consideration of terrain complexity, cumulative error, and adequate sample size. Accuracy validation and evaluation is accomplished using proprietary software to apply relevant statistical routines for calculation of Root Mean Square Error (RMSE) and the National Standard for Spatial Data Accuracy (NSSDA), according to Federal Geographic Data Committee (FGDC) specifications.Filtered LiDAR 1.2 data20140618Quality verified bare earth data set3-D hydrologic breaklinesNorthrop Grumman, Advanced GEOINT Solutions Operating UnitSean O'BrienProject Managermailing and physical address
301 Voyager Way
HuntsvilleAL35806USA(618) 622-8425sean.m.obrien@ngc.com8:00 - 5:00The Bare Earth DEM was extracted from the raw LIDAR products and attributed with the bare earth elevation for each cell of the DEM. Bare Earth DEMs do not include buildings, vegetation, bridges or overpass structures in the bare earth model. Where abutments were clearly delineated, this transition occurred at the junction of the bridge and abutment. Where this junction was not clear, the extractor used their best estimate to delineate the separation of ground from elevated bridge surface. In the case of bridges over water bodies, if the abutment was not visible, the junction was biased to the prevailing stream bank so as not to impede the flow of water in a hydrographic model. Bare earth surface includes the top of water bodies not underwater terrain, if visible.Bare earth LiDAR returns201406181-meter bare-earth DEMNorthrop Grumman, Advanced GEOINT Solutions Operating UnitSean O'BrienProject Managermailing and physical address
301 Voyager Way
HuntsvilleAL35806USA(618) 622-8425sean.m.obrien@ngc.com8:00 - 5:000There is not a systematic method of testing when testing horizontal accuracy in LiDAR. The horizontal accuracy is checked by collecting building corners during the survey. Lines are then digitized representing the building outline and the differences are measured from each individual survey point to the corner of the building outline. Stats are calculated to ensure horizontal tolerances are met. These measurements resulted in an RMSEr of 1.86 meters and equals a RMSE accuracy 3.21 meter horizontal accuracy at the 95 % confidence level. Reporting FVA calculations to meet NSSDA specifications RMSE of 12.5 cm. Vertical accuracy requirements follow the NSSDA specifications based on RMSE of 12.5 cm in open terrain land cover category. This assessment verifies the vertical accuracy of the LiDAR derived DEM shall be calculated and reported in three ways. 1. FVA 2. SVA 3. CVA. Additionally the FVA points were assessed against the TIN derived from the LAS LiDAR point cloud controlled and calibrated swath data to ensure they met the required accuracy of 12.5cm RMSEz and 24.5cm at the 95% confidence interval.0.168 meters (0.55 ft)Value represents the Fundamental Vertical Accuracy (FVA) assessment at the 95% confidence interval of the survey checkpoints verified against the TIN derived from the final controlled and calibrated swath data.0.145 meters (0.48 ft)Value represents the Fundamental Vertical Accuracy (FVA) assessment at the 95% confidence interval. This represents the FVA checkpoints compared against the derived DEM at the 95% confidence interval.0.196 meters (0.64 ft)Value Represents the Supplemental Vertical Accuracy (SVA) results Tall Weeds and Crops Land Cover Class reported at the 95th Percentile. SVA checkpoints were assessed and reported against the derived DEM.Value Represents the Supplemental Vertical Accuracy (SVA) results Forested and Fully Grown Land Cover Class reported at the 95th Percentile. SVA checkpoints were assessed and reported against the derived DEM.0.319 meters (1.05 ft)Value Represents the Consolidated Vertical Accuracy (CVA) results all Land Cover Classes combined and reported at the 95th Percentile. CVA checkpoints were assessed and reported against the derived DEM.0.236 meters (0.77 ft)Value represent horizontal accuracy assessment at the 95% confidence interval.3.21 meters (10.53ft)RasterUniversal Transverse Mercator180.999600-93.00000.0000000500000.0000000.000000coordinate pair0.0010000.001000metersNorth American Datum of 1983Geodetic Reference System 806378137.000000298.257222North American Vertical Datum of 19880.001000metersExplicit elevation coordinate included with horizontal coordinatesBare-Earth DEM Tiles .img format After a satisfactory review of the classified point cloud tiles, these tiles are used to create the Bare Earth DEM raster tiles. Using TerraModeler version 013, the classified point cloud tiles and hydro flattened breaklines are combined to create triangulated surface models and exported as lattice files, in ArcInfo ASCII raster format, with a cell size of 2.0 meters. The Digital Elevation Model (DEM) naming convention matches the classified LAS tiling scheme. The ASCII raster files are verified to contain no NODATA pixels, within the Area of Interest.
The ASCII raster files are converted to ESRI Float Grid format and clipped to the project coverage area. The bare earth Grid tiles are reviewed to ensure that there is a seamless data set, with no edge artifacts or mismatches between tiles. Any areas outside the Area of Interest, but within the tiling scheme, are coded with a unique NODATA value. The projection for this data set is UTM Zone 18N, NAD83, meters20140620Northrop Grumman, Advanced GEOINT Solutions Operating UnitSean O'BrienProject Managermailing and physical address
301 Voyager Way
HuntsvilleAL35806USA (618) 622-8425sean.m.obrien@ngc.com8:00 - 5:00FGDC Content Standards for Digital Geospatial MetadataFGDC-STD-001-1998local timeTo be determined by clientnoneGeographyUnclassifiedInformation UnclassifiedSeneca NY Watershed LiDARAny conclusions drawn from the analysis of this information are not the responsibility of Northrop Grumman, USGS or its partners.USGS/NGTOC
Pat Emmett
1400 Independence Road
Rolla, MO 6541LiDAR DatasetUSGS/NGTOCPatrick Emmettmailing and physical address1400 Independence RoadRollaMO65401USA573-308-3587