LiDAR Contours - Rivers North 1 Foot Interval | |
Data format: Shapefile File or table name: Rivers_LiDAR_Contours1ft_North Coordinate system: Universal Transverse Mercator |
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Abstract:
The layer shows 1 foot contours of the northern section of the Rivers, Manitoba LiDAR project area. LiDAR data was collected using LSI's proprietary Helix LiDAR system - Novatel GPS and IMAR inertial unit, coupled to a Riegl Q560 digital waveform ranging laser and mounted in a Cessna 185 aircraft. LiDAR was collected at 600m AGL, and a ground speed of 170km/h. Data is in an ASCII XYZ coordinate format. |
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The layer shows 1 foot contours of the northern section of the Rivers, Manitoba LiDAR project area. LiDAR data was collected using LSI's proprietary Helix LiDAR system - Novatel GPS and IMAR inertial unit, coupled to a Riegl Q560 digital waveform ranging laser and mounted in a Cessna 185 aircraft. LiDAR was collected at 600m AGL, and a ground speed of 170km/h. Data is in an ASCII XYZ coordinate format.
The data was collected in order to build an accurate digital elevation model of the study area. The contour data was generated from this DEM.
ground condition
none
1007 Century Street
This data set was developed for Province of Manitoba by LiDAR Services International Inc.
Ground points were initially classified using an automatic classification routine. The ground surface model was edited and verified by creating a shaded relief model and identifying erroneous points and voids in the ground surface.
Data was verified by viewing shaded relief models. Points were checked against those from adjacent flightlines to ensure positional accuracy. The intensity of the LiDAR returns was viewed and compared against adjacent data to verify horizontal positional accuracy.
Horizontal accuracy is verified by comparison of horizontally identifiable features in the LiDAR data against similar features in another flightline of LiDAR data over the same geographic area. Horizontal accuracy is also verified against known coordinates of building roof edges at the calibration site used for that flight.
Vertical accuracy is verified by comparison of points from the calibration flights to conventionally surveyed ground points at the calibration site.
Control point used to build GPS network from which positions of kinematic GPS solution and calibration points were derived. NAD83 published coordinates are Lat: 49 53 09.2928, Long: -99 54 41.0588, Ellipsoid Height: 373.841m. NAD 83 adjusted coordinates are Lat: 49 53 09.29264, Long: -99 54 41.05828, Ellipsoid Height: 373.846m. This point was not occupied during kinematic GPS collection.
Control point used to build GPS network from which positions of kinematic GPS solution and calibration points were derived. NAD83 adjusted coordinates derived from Assiniboine River LiDAR survey (2007) are Lat: 50 02 57.33065, Long: -100 21 08.44169, Ellipsoid Height: 462.327m. This point was occupied during kinematic GPS collection; adjusted coordinates were used during processing.
Control point used to observe during kinematic collection from which positions of kinematic GPS solution were derived. NAD 83 adjusted coordinates are Lat: 49 54 12.93657, Long: -99 56 44.43657, Ellipsoid Height: 383.146m. This point was occupied during kinematic GPS collection.
GPS static network was processed and adjusted, and kinematic GPS data was processed using coordinates obtained from the static network adjustment. Kinematic GPS and inertial information were combined to create the final position and attitude trajectory. The position and attitude trajectory was combined with data from the scanning laser to produce a raw XYZ point cloud.
250, 3115 12th Street NE
Overlapping flight lines were compared at the calibration site and within the project area to determine the boresight corrections required to remove systematic errors. Raw point clouds were generated using the attitude information and scanning laser ranges.
250, 3115 12th Street NE
Raw XYZ point clouds were combined and divided into 1km x 1km tiles. Redundant data between overlapping flightlines was removed.
#250, 3115 12th Street NE
An automatic ground classification routine was run on the LiDAR data using TerraScan, and the results were verified by viewing a shaded relief model. Points that existed above ground were classified to vegetation and then buildings were classified manually from the vegetation points using the shaded relief model to identify them. Points that could not be identified as vegetation or ground were classified as non-ground; bridges , trains, and transmission structures were classified to non-ground.
250, 3115 12th Street NE
LiDAR data was adjusted from ellipsoid to orthometric elevation using the CGVD28 height model.
#250, 3115 12th Street NE
A gridded ASCII XYZ file with a horizontal spacing of 1m was created. Elevations were derived from triangle facets in the TIN model (built using ground points only) at the centre of the grid cell.
#250, 3115 12th Street NE
A surface was created from the ground, vegetation, building, and non-ground points in TerraScan, and a gridded ASCII XYZ file with a horizontal spacing of 1m was created. Elevations were derived from the highest point elevation within the grid cell.
#250, 3115 12th Street NE
copied compressed .gz files to local disk unzipped using 7 ZIP created a grid from the first text file to be used as the snap grid CREATETIN GENERATE POINT TINARC POINTGRID ran aml called ld_lidar_grid to generate grids from all text files used mosaic to new grid in arcgis toolbox 9.2 used 32 bit float 1.0 metre cell mean used con(isnull (lidar), focalmean(lidar, rectangle, 3, 3,), lidar) to fill in gaps between the tiles of data. Morden full feature grids and bare earth grids were successfully created
Multiplied the DEM grid by 3.28084 to convert elevation values from meters to feet. Used the CONTOUR command in ArcInfo GRID to generate contour lines at 1-foot intervals. Ran the RENODE command on the resulting coverage to renumber arc nodes and update FNODE# and TNODE# values in the arc attribute table (AAT). In ArcEdit, deleted arcs where FNODE# = TNODE# and the length was less than or equal to 110-meters. Converted the ArcInfo coverage to a shape file.
Dataset copied.
Internal feature number.
ESRI
Feature geometry.
ESRI
Length of feature in internal units.
ESRI
The only attributes assigned were point classification during the processing phase using TerraScan. See process steps for details.
None
250, 3115 12th Street NE