| LiDAR for the La Salle Watershed Upstream of Elie | |
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Data format: Raster Dataset - GRID File or table name: es44_wslas Coordinate system: Universal Transverse Mercator Theme keywords: elevation, digital elevation model, LiDAR, Light Distance and Ranging, geoscientific information, environment, Earth Science > Land Surface > Topography > Terrain Elevation |
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Abstract:
A Digital Elevation Model (DEM) was produced for an area of approximately 190 square kilometres in the headwaters of the La Salle River upstream of Elie, Manitoba. The LiDAR system combines laser, GPS and Inertial technology to measure the earth's surface. Three-dimensional points are collected, from which a bald earth ground model can be derived. For deliverables, 78 ground thinned tiles in a 1-metre evenly spaced grid to create a Digital Elevation Model (DEM) for the study area were supplied. The data was captured by Fugro Horizons as an add-on to a Manitoba Provincial project that was capturing a swath of LiDAR data along the La Salle River centerline. |
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A Digital Elevation Model (DEM) was produced for an area of approximately 190 square kilometres in the headwaters of the La Salle River upstream of Elie, Manitoba. The LiDAR system combines laser, GPS and Inertial technology to measure the earth's surface. Three-dimensional points are collected, from which a bald earth ground model can be derived. For deliverables, 78 ground thinned tiles in a 1-metre evenly spaced grid to create a Digital Elevation Model (DEM) for the study area were supplied. The data was captured by Fugro Horizons as an add-on to a Manitoba Provincial project that was capturing a swath of LiDAR data along the La Salle River centerline.
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. The ESRI GRID format allows for analysis involving elevation data and also provides for the possibility of contour generation. The data is to define the watershed sub-basin with high resolution elevation information to improve hydrologic modeling within the area.
ground condition
N/A
200 - 303
Attribute accuracy was performed using a histogram with a lower limit of -0.15m and upper limit of +0.15m as its confidence interval (i.e. 1 standard deviation) to determine how many points fell within tolerance. From analysis the data was within specification.
4247 Survey points were used in comparison with the Elie Elevation data. 3770 of the survey points fell within the deviation of ± 0.15cm. 477 of the survey points were outside of the specifications. Exact Values: Bin Frequency -0.3 3 -0.15 321 0 1644 0.15 2126 0.3 153 More 0
Data was verified by ground survey verification using a survey-grade RTK Trimble GPS. Natural Resource Canada's geodetic monuments were used for identifying erroneous points.
Coverage of the DEM is outlined by the Stream of Elie Sub-watershed. There are no voids or omissions.
Horizontal accuracy is verified in a comparison of Lennon Trilogy data (a partner with Fugro Horizon) and Agri-Envionment Services Branch data. 3 points were used in determining horizontal accuracy.
See attched report for full details.
Vertical accuracy is verified in a comparison of Lennon Trilogy data (a partner with Fugro Horizon) and the DEM. Multiple cultivation and road points from LTL were verified tolerances.
When comparing the Lennon Trilogy test points to the LiDAR elevation, areas that were within a 0.15m deviation were within tolerance.
78 Individual tiles were mosaicked in ArcCatalog. The tiles are a raster product derived from 1m evenly spaced grid of three dimensional points. Each tile is 2000 metres by 2000 metres and in a Universal Transverse Mercator Projection (UTM), Zone 14, on the North American Datum 1983 (NAD83). For verification purposes AESB conducted ground survey verification using a survey-grade RTK Trimble GPS. Natural Resource Canada's geodetic monuments were used for the control points for the AESB survey. The Fugro LiDAR points were imported into Microsoft Excel from the ArcGIS point shape files. Within Excel, histograms were created to display LiDAR point elevation data. The histograms display the frequency of difference between the surveyed points and LiDAR imagery. The histogram results are based on road data and cultivation data. The LiDAR point file was converted to a raster 1m pixel cell size and calculated against the LiDAR imagery. The histograms from Figure 1 (in the attached document) use a lower limit of -0.15m and upper limit of +0.15m as its confidence interval (i.e. 1 standard deviation).