Data format: Raster Dataset
File or table name: e204_pe.img
Coordinate system: Universal Transverse Mercator
Theme keywords: elevation, Earth Science > Land Surface > Topography > Terrain Elevation
| Bare Earth LiDAR DEM for a portion of the Pembina River basin in North Dakota | |
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Data format: Raster Dataset File or table name: e204_pe.img Coordinate system: Universal Transverse Mercator Theme keywords: elevation, Earth Science > Land Surface > Topography > Terrain Elevation |
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Abstract:
Description of data and location to be completed by client. LiDAR data was collected using LSI's proprietary Helix LiDAR system - Novatel GPS and SPANS inertial unit, coupled to a Riegl Q560 digital waveform ranging laser and mounted in a Cessna 185 aircraft. LiDAR was collected at 500m AGL, and a ground speed of 230km/h. Data is in an ASCII XYZ coordinate format. |
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Metadata elements shown with blue text are defined in the Federal Geographic Data Committee's (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM). Elements shown with green text are defined in the ESRI Profile of the CSDGM. Elements shown with a green asterisk (*) will be automatically updated by ArcCatalog. ArcCatalog adds hints indicating which FGDC elements are mandatory; these are shown with gray text.
Description of data and location to be completed by client. LiDAR data was collected using LSI's proprietary Helix LiDAR system - Novatel GPS and SPANS inertial unit, coupled to a Riegl Q560 digital waveform ranging laser and mounted in a Cessna 185 aircraft. LiDAR was collected at 500m AGL, and a ground speed of 230km/h. Data is in an ASCII XYZ coordinate format.
DEM's can be used as source elevation data for digital orthophotos, and, as layers in geographic information systems, for earth science analysis. DEM's can also serve as tools for volumetric analysis, for site location of towers, or for drainage basin delineation.
David Ronneberg LiDAR Services International Inc. PH. 403 517 3130 Fax 403 291 5390 250, 3115 12th Street NE Calgary, Alberta T2E 7J2 Canada
ground condition
Any conclusions drawn from analysis of this information are not the responsibility of the Red River Basin Commission (RRBC), nor any of its partners.
200 - 303 Main Street
This data set was developed for Red River Basin Commission 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.
There are 8 small voids in the dataset. See included information for more details.
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 the conventionally surveyed buildings at the calibration site.
Control point used to build GPS network from which positions of kinematic GPS solution and calibration building were derived. NAD83 published coordinates are Lat: 49 00 02.51410, Long: -97 32 57.71230, Ellipsoid Height: 227.173m. NAD 83 adjusted coordinates are Lat: 49 00 02.51431, Long: -97 32 57.71289, Ellipsoid Height: 227.155m. 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 building were derived. NAD83 published coordinates are Lat: 49 00 54.23770, Long: -98 09 19.91450, Ellipsoid Height: 434.335m. NAD 83 adjusted coordinates are Lat: 49 00 54.23733, Long: -98 09 19.91326, Ellipsoid Height: 434.387m. 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 building were derived. NAD83 published coordinates are Lat: 49 00 02.77270, Long: -97 26 14.52050, Ellipsoid Height: 217.248m. NAD83 adjusted coordinates are Lat: 49 00 02.77281, Long: -97 26 14.52114, Ellipsoid Height: 217.264m.
Control point used to build GPS network from which positions of kinematic GPS solution and calibration building were derived. HASKETT is the name given by LSI to the section corner monument located to the north-east of the town of Haskett with the marker inscription "WT-10-820N T 1 R 4 W 1993". There were no published coordinates provided for this point. NAD83 adjusted coordinates are Lat: 49 00 54.58772, Long: -97 51 50.00723, Ellipsoid Height: 252.417m.
Control point used to build GPS network from which positions of kinematic GPS solution and calibration building were derived. MORDEN1 is the name given by LSI to the point established at the Morden Airport, monumented with a temporary spike. NAD83 adjusted coordinates are Lat: 49 12 29.40117, Long: -98 03 16.85126, Ellipsoid Height: 265.544m.
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 positively be identified as non-ground features (farm equipment in the middle of a field, vehicles on a road, transmission structures and telephone poles 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
The ASCII XYZ (bare earth) grid was imported to ArcGIS 9.1. The grids were mosaicked together, and then a hillshade was produced from the grids (Azimuth:270, Elevation:55, No Shadows, Z-scale:1.0). The hillshades were produced in 5km x 5km tiles.
#250, 3115 12th Street NE
Tiles were mosaiced together into two blocks, One block containing the western half of the coverage area and the other block the eastern half. This was done so that it could be mosaiced as a ArcInfo GRID. There are limiting factors when creating these grids such as number of files that can be mosaiced at one time and the size of the output file. Once the blocks were created they were exported to Imagine files.
In ERDAS Imagine recalculated the Statistics on the images with the skip factor set to 1. Assigned a projectio0n of NAD83 Zone 14N to each file. Mosaiced the two blocks into one. Recalculated the Statistics with the skip factor set to 1.
Metadata imported.
The only attributes assigned were point classification during the processing phase using TerraScan. See process steps for details. The only attributes are the elevation values and the encoded values for easting and northing coordinates. There are no attached attribute tables.
None
250, 3115 12th Street NE