South Carolina Statewide LiDARAcquisitionSouth CarolinaDepartment of Natural ResourcesTechnology Development ProgramColumbia, South Carolinahttp://www.dnr.sc.govSCARC GIS - February 12, 2013Holly M. GillamSpatial Data Managergillamh@dnr.sc.govGeoff SchwitzgebelGIS Applications Managerschwitzgebelg@dnr.sc.gov
Slide provided by: Gary MerrillU.S. Geological Survey(803) 750-6124, email@example.comProject PrincipalsJim ScurryTechnology DevelopmentProgram DirectorSC Dept. of NaturalResourcesGary MerrillUSGS Geospatial Liaisonto the CarolinasNSDI Partnership OfficeU.S. Geological Survey
2007 2008 2009 2010 2011 2012Vendor PhotoScience Furgo Earthdata Sanborn Sanborn Dewberry DewberryQA/QC unknown Dewberry Dewberry Aerometrics AerometricsProjectCoordinatorNOAA SCDNR/USGS * SCDNR/USGS * SCDNR/USGS * SCDNR/USGS * SCDNR/USGS *ǂ - NOAA contributed LiDAR data from 2007 project to statewide effort* - Also includes monetary and in-kind contribution from numerous federal, state, county, and local entitiesǂLiDAR Acquisition for SCYear & VendorGeoreferencing of lidar points uses GPSto derive the position of the aircraft, INS todetermine the pointing direction of thesensor, and the lidar range to extrapolatethe coordinates of a target point on theground.Source: ASPRS
Delivered LiDAR Data and Data Products• Raw LiDAR data (LAS format)• Intensity Images• Bare Earth Terrain Surface• Hydrobreaklines• Metadata• LiDAR Report• County-wide data setsLASIntensity ImageBare-earth Terrain Surface Hydrobreaklines DEM
LiDAR Data Format• Raw LiDAR - LAS file format , 1.4 meter nominalpoint spacing, 18.4 cm vertical RMSE• LAS files delivered as 5000’ x 5000’ tiles following SCGeodetic 1:200 scale index naming convention• Point Cloud Classes• Class 1 - Unclassified (non-ground)• Class 2 - Ground (bare-earth extra points)• Class 8 - Model Key Point (thinned bare-earth)• Class 9 - Water (water as defined from the hydro enforcementprocess)• Class 12 - Overlap Points (overlap from adjoining flight lines)• Note: Points for Bridges and box culverts are in Class 10 forthe 2009/2010 and Class 13 for 2012 acquition
ASPRS LAS formatClassificationClass2007 2008 2009 2010 2011 2012Unclassified 1 X X X X X XGround (bare-earth) 2 X X X X X XLow Vegetation 3 ---- ---- ---- ---- ---- ----Medium Vegetation 4 ---- ---- ---- ---- ---- ----High Vegetation 5 ---- ---- ---- ---- ---- ----Building 6 ---- ---- ---- ---- ---- ----Noise 7 ---- ---- ---- ---- ---- ----Model Key-point(Thinned bare-earth) 8---- X X X X XWater 9 ---- X X X X XReserved 10---- ----Bridges and boxculverts---- ----Reserved 11 ---- ---- ---- ---- ---- ----Overlap Points 12 ---- ---- ---- ---- ---- ----Reserved 13---- ---- ---- ---- ----Bridges and boxculvertsReserved 14-31 ---- ---- ---- ---- ---- ----ASPRS class used for LAS point cloud dataPoint data for this class put into Class 1, unclassifiedOptional use by vendor following ASPRS standard----LAS Point Classes by Project Year
QA/QC LiDAR Data• Independent QA/QC of LiDAR dataSCDNR / USGS• Confirm edits from Independent check if required andrecommendations.• Criteria into two sections Usability and Data.• Software:• ESRI ArcGIS Desktop• ESRI 3D Analyst Extension• Merrick MARS ExplorerUsability:• Coordinate system• Data products complete• Data products follow format• Metadata• ReportData:• hydrofeatures follow standard• Inspect terrain surface for anomalies• generate hillshade, inspect for issues• LAS if required
SCDNR’s usability QA/QC on the LiDAR data products Overview:•Coordinate System: passedConfirmed the coordinate system for the LAS files using MARS software andthe Geodatabase in ArcCatalog.•Metadata: passedComplete: Separate xml file was provided for each of the features in theTerrainGeodatabase and an overall metadata file for the LAS and Intensity Images.The final report.•Hydrobreaklines: passedA separate geodatabase with just hydrobreakline data set was provided.•Intensity Images: passedData includes intensity images for Sumter County.Images follow tiles and naming convention using SC Geodetic Survey 1:200scale index.•Terrain: passedNo void areas.County boundary is covered., 1000’ bufferNote: the tile levels where determined by vendor.•DEM:DEM is in the Terrain geodatabase using the linear method.Raster Information: Cellsize 10 x 10 ft, GRID, floating points, 32 bit.LAS Point File Information (follows SC Geodetic Survey 1:200 scale index namingconvention)•Point Spacing Range: 1.338 – 7.007•Z Minimum: (-391.67) – (+273.33)•Z Maximum: (+178.9) – (+5566.71)SCDNR’s usability QA/QC onthe LiDAR data products Overview
LiDAR CheckISSUE: Charleston Terrain and DEM contains void areas and short required buffer fromcounty boundary.RESOLUTION: Recreate masspoints to include missing LAS tiles along Berkeley andCharleston County boundary. Rebuild terrain surface, and DEM.
ISSUE: Points misclassified in class 2 & 8,Need to be in class 1 - unclassifiedLAS data viewed in MARS SoftwareRESOLUTION: Points moved from class 2 and 8to class 1 in LAS tile. Update masspoints,recreate Terrain surface, and DEM
ISSUE: Location marked aspossible issue in terrain basedDEM.RESOLUTION: No action required.Location is an entrance/exit to aparking garage.
ISSUE: Location marked aspossible issue in terrainsurface.RESOLUTION: Verified pointsclassified in the incorrect class. Pointsin class 8 should be moved in class 1.Update masspoints, rebuild terrain, andDEM
Tile 977402-03.lasISSUE: LAS tile has points classified inclass 1 that should be in class 2 and 8.RESOLUTION: Move points into correct classification. Updatemasspoints, rebuild terrain surface, and DEM
ISSUE: Single line stream used as a datasource to build terrain with soft line optioninstead of hard line.Resolution: Change the Sftype option to hardline and rebuild Terrain.Properties of Terrain Surface
RESOLUTION: Delete points from LAS tile ormove points to Class 1 – unclassified.Note: Not an issue in the terrain surface if theboundary used does not include areas inquestion.ISSUE: LAS points beyond CountyBoundary buffer are not classified.
Note: LAS data for 2008 removed any points outside theproject boundary.
Note: LAS data for 2011 and 2012 have points outside of the project boundaryand may be incomplete for some tiles.
Bare-earth Terrain SurfaceGround only Hydro Enforced Hydro FlattenedFeature Classes in Terrain Surface:• Masspoints• Project BoundaryFeature Classes in Terrain Surface:• Masspoints• Hydrofeature• Islands• LiDAR Extent• WaterbodyFeature Classes in Terrain Surface:• Masspoints• Hydrofeature Banklines• Islands• LiDAR Extent• Waterbody
LAS to MasspointsCreate a file Geodatabase and a new feature data set. Save the Multipoint feature class to thisfeature data set.ArcToolbox• 3D Analyst Tools Conversion From File LAS to Multipoint• Average point spacing: 3• Input class Codes: 2, 8 (bare earth)Requires 3D Analyst Extension
New Terrain Surface (Ground Only)• ArcCatalog• In the File Geodatabase , create a new terrain inthe feature data set.• Select the data sets that will make up terrainsurface
Hydroenforced Terrain Surface
Hydro Flattened Terrain Surface
ArcToolbox• 3D Analyst Tools Conversion From Terrain Terrain to Raster• Options: Float, Natural_Neighbor, CELLSIZE 10, Processing ExtentTerrain to DEMBare-earthTerrainSurfaceDEMRound extent values to the nearesttenth or higherRequires 3D Analyst Extension
Natural Neighbor Method Linear MethodFlorence County, SC LiDAR2-foot Topographic Contours(from 5-foot DEMs)1:500-scaleOpen Drain Closed DrainComparisonSlide provided by: Gary MerrillU.S. Geological Survey(803) 750-6124, firstname.lastname@example.orgStep 1: ArcToolbox 3D Analyst Tools Conversion From Terrain Terrain to RasterStep 2: ArcToolbox 3D Analyst Tools Raster Surface Contours or Contours with Barriers
ArcToolbox• 3D Analyst Tools Raster Surface From Terrain Hillshade• Options: use default settingsHillshade fromTerrain BasedDEMDEMHillshadeRequires 3D Analyst Extension
Ground OnlyHydro flattened(no island constraints)Hydro flattened(with island constraints)Hydro enforcedHYDROFEATURE
Terrain BasedDEM to 2ftContoursArcToolbox• 3D Analyst Tools Raster Surface Contour with Barriers• Options: Save to output to a file geodatabase, enhance by using Indexed intervalDEMRequires 3D Analyst ExtensionContour
USGS NHD 1:24,000Hydrography Data Set
LiDAR based Hydrobreaklines
LiDAR HydrobreaklinesUSGS Hydrography vs.HydrofeatureLAS Point DataHydrofeatureNHD Hydro
ISSUE: Elevation of waterbodyhigher than adjacent ground.RESOLUTION: Updatehydrobreakline with correctelevation value. Recreateterrain surface and DEM.
• http://mappingcenter.esri.com/index.cfm?fa=arcgisResources.gateway• ColorRamps3.0• Elevation/Bathymetry• ShadeMax Color Ramps Hypsometry styleElevation Color Ramps
Layer order Hillshade: created from LiDAR based DEM (10’x10’ cell size)• Color Ramp Black to White: color 1-black , color 2-white, Algorithm: HSV• Transparency: 50% Contours 25’ foot intervals: from LiDAR based DEM• minor: Color CMYK 0,25,36,36; Width=0.40• major: Color CMYK 0,25,36,37; Width= 1.20• Transparency: 0% Municipality Boundary• color RGB 255, 211, 127• Transparency: 0% DEM (10’x10’ cell size)from Terrain Surface• Color Ramp Fern greento yellow:Color 1-HSV 99, 50, 80,Color 2-HSV 60, 25, 100Algorithm: HSV• Transparency: 0%Map Reference scale 1:54,000LiDAR Based Cartographic Maps
LiDAR Derived Products
Digital Elevation Model (DEM)Digital Surface Model (DSM)Intensity ImagesSlopeAspectRaster Products
LiDAR Derived ProductsVector Products:•Building Footprints•Applying Building Heights•Contours•Line of Sight•Derived Shorelines•Tree CanopiesOther:•ESRI Terrains
Digital Elevation Model (DEM)•Ground Only•Class 2 and 8 used•Can be created from LAS Dataset, TIN or Terrain
•Only delineates features above the ground•Class 1 points used (Unclassified)•Use last returns – This includes single returns•Helps filter out some excess tree canopiesDigital Surface Model (DSM)
•Use last returns – This includes single returns•Helps filter out some excess tree canopiesDigital Surface Model (DSM)All Returns Last Returns
nDSM used to get actual surface heightsnDSM = DSM – DEMNormalized Digital Surface Model (nDSM)DSM (Canopy)Class 1DEM (Ground)Class 2 and 8-
•Based on the reflective intensity of a LiDAR pulse.•Looks similar to a panchromatic aerial photo•Can be used in place of aerial photography if not availableIntensity Images
Building Footprints•Approximate building outlines can be created•May need to have Class 6 (buildings) processed to getthe most accurate results•Building filters can be applied using 3rd party softwaresuch as Merrick’s MARS software
Building Footprints•Approximate building outlines can be delineated•Filter nDSM values based on desired height values to beevaluatedResidential with minimal tree cover Residential with tree cover
Applying Feature Heights•Radio Towers, Well Locations, Buildings, etc•Various tools available to add height valuesAdd Surface Information (3D) Zonal Geometry As Table (SA)
LAS Datasets – On The Fly DataCan provide 4 layers on the flyElevation SlopeAspectContours
LAS Datasets – Filter PropertiesFilter LAS Display by Class Number and Return Type1.2.
LAS Datasets – Surface ConstraintsCan enforce on the fly layers with hydro breaklines, bridges,culverts, etc
ABCDEFGHIALAS Dataset Symbology in ArcGISTable of Contents: Properties for LAS Data set
LAS Datasets – On The Fly DataElevation - SurfaceLAS Dataset Properties
LAS Datasets – On The Fly DataContours and TerrainLAS Dataset Properties
LAS Datasets – On The Fly DataCartographic Output
How Do I Obtain LiDAR Related Data?Raw LAS File Download– USGS CLICK http://lidar.cr.usgs.gov/– NOAA Digital Coasthttp://www.csc.noaa.gov/digitalcoast/data/coastallidar/index.htmlLiDAR Data Products (DEM, Hydrobreaklines, Intensity Images, Terrainsurface, Contours)– SCDNR http://dnr.sc.gov/GIS/lidar.htmlDEM Download– USGS National Elevation Dataset (NED) http://ned.usgs.gov/Statewide 200 scale Index– SC Geodetic Survey http://www.gis.sc.gov/data.html
How Do I Obtain LiDAR Related Data?Available Vendor and SCDNR Derived LiDAR Productshttp://dnr.sc.gov/GIS/lidarstatus.html• Organized by County• Includes:• DEM (10’x10’ grid)• Hydro breaklines• Intensity Images• Terrain surface• Contours (2 foot interval)Raw LAS Tiles Not AvailableThrough the DNR
Download the *.exe and ALLof *.rar files with the countyname in it to the same folder1open the *.exe file touncompress the files2Follow prompts to extract.3Compressed Terrain on FTP ServerSoftware used: WinRARAbility to split files into volume sizes.Note: Users are not required to have software to uncompressfiles.
How Do I Obtain LiDAR Related Data?Raw LAS File Download– USGS CLICK http://lidar.cr.usgs.gov/– NOAA Digital Coasthttp://www.csc.noaa.gov/digitalcoast/data/coastallidar/index.htmlDEM Download– USGS National Elevation Dataset (NED) http://ned.usgs.gov/
Jim Scurry, Technology Development Program DirectorSouth Carolina Department of Natural ResourcesPhone:(803) email@example.comGary Merrill, Geospatial Liaison to SCU.S. Geological SurveyPhone: (803) firstname.lastname@example.orgSC LiDAR Consortium ProgramHolly Gillam , Spatial Data ManagerSouth Carolina Department of Natural Resourcesgillamh@dnr.sc.govGeoff Schwitzgebel, GIS Applications ManagerSouth Carolina Department of Natural Resourcesschwitzgebelg@dnr.sc.govOther Questions?
SC Statewide LiDAR AcquisitionProject PrincipalsJim ScurryTechnology Development ProgramDirectorSC Dept. of Natural Resources(803) 734-9494ScurryJ@dnr.sc.govGary MerrillUSGS Geospatial Liaison to the CarolinasNSDI Partnership OfficeU.S. Geological Survey(803) email@example.com