LiDAR Dataset - Calvert Island - 2012 & 2014

This is the metadata record for the LiDAR datasets acquired for Calvert Island area, BC, Canada, in 2012 and 2014. It provides details on the two LiDAR missions and the initial processing to merge the two datasets together.

The dataset was created from two missions - one in 2012 and one in 2014. The two datasets were merged together and used to generate numerous derived data products (see the links section below). The 2012 mission collected hyperspectral and orthophotos so the mission metadata for the LiDAR dataset also applies to those assets.

Terrain elevations measured by airborne LiDAR were collected in August 2012 for Calvert Island, Hecate Island, and three other survey areas located to the northeast (i.e., mouth of the Koeye River, port town of Namu, and the southwest corner of King Island) by Terra Remote Sensing Inc. (TRSI), Sidney, BC (Figure 1). The total aerial coverage of the acquisition was 477.2 km2. The point density (number of returns per unit area) of the acquisition averaged approximately 2.34 pts/m2 for all posted returns (maximum of three discrete returns per pulse), 2.11 pts/m2 for first returns, and 0.51 pts/m2 for ground-classified returns. More detailed information on the TRSI LiDAR sensor and survey settings, data pre-processing, and quality checks and accuracy verification is given in 000-2087_CalvertIsland_DataAcquisitionReport_v2.pdf. A second airborne LiDAR data acquisition was undertaken by the LiDAR Research Group, University of Northern BC (UNBC) in August 2014, with the express purpose of collecting higher spatial resolution (3.4–22.3 pts/m2) LiDAR data over selected research areas of interest on Hecate and Calvert Islands, as well as to infill and eliminate several data voids found in the initial TRSI LiDAR coverage (see, 1408007_calvert_meta.pdf for further details).

The original LiDAR data collected by TRSI has undergone two levels of refinement since their initial delivery. First, the Coastal Erosion & Dune Dynamics (CEDD) Laboratory, University of Victoria, completed a manual refinement of the automated ground point classification originally created by TRSI. The automated ground classification and its manual refinement were generated using TerraScan and MARS software, respectively. Manual refinement of the LiDAR point classes was limited to geographic regions of the dataset covering Hecate and Calvert Islands only. All other areas have the original automated ground classification produced by TRSI. Second, two large data voids in the 2012 TRSI LiDAR coverage were infilled using 2014 UNBC LiDAR data. Geometric adjustment and merger of these two point clouds focused exclusively on minimizing offset errors in the vertical (z) dimension. Lack of local geodetic control (benchmarks) and targets within the survey area prevented further adjustments in the horizontal (x,y) domain. Also, because of inherent technical incompatibilities between TRSI and UNBC LiDAR sensors (i.e., maximum number of returns per pulse: three vs. seven), it was impossible to merge the point attribute storing the return number in any meaningful way. We, therefore, caution against computing and using LiDAR metrics that are dependent on return number. Methodological details of the point merger are given in UNBC2TRSI_Z_POINT_CONVERSIONS_v2.pdf.

Some basic information about the dataset is provided below. For more detail please refer to the links provided.

2012 Mission: Dates: August 5th, 15th ,and 17th Conducted by: Terra Remote Sensing Area covered: 477.22 km^2 Flight height: 1150 meters above ground level Projection: UTM Zone 9 Datum: NAD 83 Geoid: HT 2.0 LiDAR points: a relative accuracy of +/-15 cm and absolute accuracy of 1m Hyperspectral Data: +/- 2 pixel Point cloud density: Taking random samples throughout the project area, the average point density for a single flight line is 1pts/m2 Notes: Due to the fact that the majority of the area is covered by overlapping flightlines, the point density averages closer to 2 pts/m2

2014 Mission: Dates: Aug. 7, 2014 Conducted by: UNBC LiDAR Research Group Area Covered: 34.9 km^2 Flight Height: ~475 m & 650 m +/- 50m Projection: UTM Zone 9 Datum: CSRS NAD 83 Geoid: Ellipsoid heights Point density ranged from 22.3 pts/m2 to 3.4 pts/m2 LiDAR points were processed in CSRS NAD83 UTM Zone 9, but use ELLIPSOID heights. Conversion to CGVD28 was completed after DEM creation using GPS-H. Supervisor: Brian Menounos Technician: Rob Vogt Ground control: A GPS base station established by Hakai's Keith Holmes at Pruth Bay was used to position LiDAR data (see page 5 for details regarding the base station). Precise trajectory for the plane is solved using PosPac MMS. A calibration line across the base station both before and after the survey was used to aid in forward and reverse processing of the trajectory. Precise location for the base station was adjusted using NR Can's PPP. Position accuracy of the trajectory is ±3 cm.

Associated and derivative products: LIDAR Derived Forest Metrics - Calvert Island  Lidar Derived Canopy Height Model - Calvert Island 20m Digital Elevation Model - Calvert Island 3m Digital Elevation Model - Calvert Island 30m Digital Elevation Model - Calvert Island 25m Digital Elevation Model - Calvert Island Orthophoto High Compression 0.25m resolution Mosaic - 2012 - Calvert Island LiDAR-based Ecosystem Classification for Calvert Island LiDAR Derived Watersheds with Metrics - Calvert Island LiDAR-derived Drainage Network for Calvert Island Hyperspectral Imagery - Calvert Island - 2012

Access and Use

Licence: Hakai Institute

Data and Resources

Dates

Metadata Created October 26, 2018, 22:48 (UTC)
Metadata Updated October 26, 2018, 22:48 (UTC)
Reference Date(s) 2012-10-15 (Creation)
2017-01-14 (Publication)
2017-01-14 (Revision)
Frequency of Update asNeeded
Metadata Date October 17, 2018, 23:28 (UTC)

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Dataset extent

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Additional Info

Field Value
Contact Email data@hakai.org
encoding utf8
metadata-language eng
progress completed
Responsible Party Hakai Institute (Point of Contact, Processor)
spatial-reference-system 26909