Earth Systems Research Center, University of New Hampshire20211215Landsat and LiDAR-Derived Canopy Height Metrics for Central and Southeast New Hampshirevector digital dataDurham, New HampshireEarth Systems Research Center, University of New HampshireNone<URL:http://www.granit.unh.edu/data/search?dset=canopyheight_polygons/central_southeast>This polygon dataset is derived from Landsat reflectance and LiDAR elevation data. The polygon boundaries represent "image objects" that were derived using eCognition image segmentation software. The software groups image pixels into contiguous segments based on spectral reflectance. The attributes for each polygon are then calculated from the LiDAR crown height layer. Attributes include maximum, minimum, and mean elevation above the ground and standard deviation within each polygon. Elevation is in meters. This dataset incorporates Landsat imagery collected in 2018 and 2020. LiDAR data were collected in 2011 and 2012.This dataset combines Landsat reflectance data and LiDAR crown height data in a polygon format. Data represent portions of southeast New Hampshire, USA, including Rockingham County and portions of Belknap, Hillsborough, Merrimack, and Strafford Counties.2011100120200521This dataset represents portions of southeast New Hampshire, including Rockingham County and portions of Belknap, Hillsborough, Merrimack, and Strafford Counties.None planned-71.941782-70.69271043.51273142.683238NoneLiDAR, Landsat, elevationISO 19115 Topic CategoriesenvironmentelevationNoneUnited States, New England, Northeast, New HampshireNoneUsers must assume responsibility to determine the appropriate use of these data. Because of the nature of the source imagery (30m pixels), it is not recommended that the data be used at scales greater than 1:60,000.These data were developed by NH GRANIT using funding from the New Hampshire Space Grant Consortium.Esri ArcGIS 10.9.0.32739Polygon topology exists.Data are complete for the study area.Earth Systems Research Center2021LiDAR-Derived Normalized Digital Surface Model - NHraster digital dataThis data set represents a 2-meter resolution LiDAR-derived normalized Digital Surface Model (nDSM) or Canopy Height Model (CHM) for New Hampshire. It was derived from a statewide LAS Dataset which comprised 8 separate LiDAR collections that covered the state as of January, 2020. The LAS Dataset was used as input to the ArcGIS "LAS Dataset to Raster" geoprocessing tool which converted the LAS first return values to raster values in the output data set. Subsequent processing subtracted the corresponding "bare earth" surface values to produce estimated feature height. It is recognized that this is a simplistic approach to the challenge of estimating LiDAR-based first return heights. Users should recognize this and keep it in mind when using the data. This dataset comprises elevation values from the following years: 2011 2012 2014 2016 2018onLine2011050620180524ground contitionnDSMLiDAR-Derived Normalized Digital Surface Model - NH, used as basis for image segmentation.U.S. Geological Survey20200527Landsat 8 Operational Land Imager dataremote-sensing imageProduct ID: LC08_L1TP_012030_20200521_20200527_01_T1onLine20200521ground conditionOLI1Landsat 8 Operational Land Imager Dataset 1 (OLI1), used as basis for image segmentationU.S. Geological Survey20180719Landsat 8 Operational Land Imager dataremote-sensing imageSioux Falls, SDU.S. Geological SurveyProduct ID: LC08_L1TP_012030_20180719_20180731_01_T1onLine20180719ground conditionOLI2Landsat 8 Operational Land Imager Dataset 2 (OLI2), used as basis for image segmentationArcGIS Pro was used to create a mosaic of OLI1 and OLI2. Values from OLI2 were written to the output dataset where NDVI values calculated
from OLI1 were below 0.695. For all other areas, values from OLI1 were written to the output dataset.OLI1, OLI220211206OLIThe eCognition software (version 10.1, Trimble, Inc.) was used to generate image objects to depict landscape features based on reflectance
values from the Landsat 8 Operational Land Imager (OLI) and LiDAR derived canopy height measures (nDSM). The eCognition multiresolution
segmentation algorithm was used with the following settings to create the image objects; Scale paramter: 50, Shape: 0.25, and
Compactness: 0.75. Both OLI and nDSM were used as input to the algorithm and carried the same weight values. Processing was constrained to
the area defined by the Coastal, Merrimack, and Nashua LiDAR collections. The resulting image objects were subsequently exported to a shapefile.OLI, nDSM20211206Earth Systems Research CenterGRANIT Database ManagerGRANIT Database ManagerphysicalMorse Hall, University of New HampshireDurhamNH03824US(603) 862-1214(603) 862-0188granit@unh.eduVectorGT-polygon composed of chains682879State Plane Coordinate System 1983New Hampshire0.999967-71.66666742.500000984250.0000000.000000Coordinate pair0.0002080.000208Survey FeetNorth American Datum of 1983GRS 806378137.000000298.257222101CentralSoutheastObjectsCentral and Southeast NH image object polygonsEarth Systems Research CenterFIDInternal feature number.EsriSequential unique whole numbers that are automatically generated.ShapeFeature geometry.EsriCoordinates defining the features.nDSM_MAXMaximum pixel height above ground within the polygon, measure in meters.Earth Systems Research CenterEach value represents a unique elevation.nDSM_MEANMean pixel height above ground within polygon, measured in meters.Earth Systems Research CenterEach value represents a unique elevation.nDSM_MINMinimum pixel height above ground within the polygon, measured in meters.Earth Systems Research CenterEach value represents a unique elevation.nDSM_SDStandard deviation of pixel heights within the polygon, measured in meters.Earth Systems Research CenterEach value represents a unique elevation.Shape_LengFeature geometry.EsriCoordinates defining the features.Shape_AreaArea of feature in internal units squared.EsriPositive real numbers that are automatically generated.Earth Systems Research CenterGRANIT Database ManagerGRANIT Database ManagerphysicalMorse Hall, University of New HampshireDurhamNH03824US(603) 862-1214(603) 862-0188granit@unh.eduDigital data in NH GRANIT represent the efforts of the contributing agencies to record information from the cited source materials. Earth Systems Research Center (CSRC), under contract to the NH Office of State Planning (OSP), and in consultation with cooperating agencies, maintains a continuing program to identify and correct errors in these data. OSP, CSRC, and the cooperating agencies make no claim as to the validity or reliability or to any implied uses of these data.20220119Earth Systems Research CenterGRANIT Database ManagerGRANIT Database ManagerphysicalMorse Hall, University of New HampshireDurhamNH03824US(603) 862-1214(603) 862-0188granit@unh.eduFGDC Content Standard for Digital Geospatial MetadataFGDC-STD-001-1998local time