Lidar Derived Canopy Height Model - Calvert Island

Lidar Derived Canopy Height Model for Calvert Island British Columbia Canada.

Canopy Height Model has been produced by calculating first and last return LIDAR dataset (see links below for more information on the LIDAR acquisition metadata). The CHM was calculated using the bare earth model (last return) and subtracting the top of canopy (first return).

Calculated maximum laser return based on a 2 x 2 meter cell.

Lidar acquisition methods:

The Canopy Height Model is derived from a merge of two lidar datasets acquired at different times.

  1. 2012 acquisition by Terra Remote Sensing On August 5th, 15th,and 17th, 2012, TRSI collected hyperspectral, lidar and digital image data in four project sites at and near Calvert Island, B.C. using a fixed wing aircraft with lidar system and hyperspectral sensor. A combined GPS/INS System (Inertial Navigation System) is used for aircraft attitude and position. A total of 477.22 km2 was covered on this mission. Flight height was 1150 metres AGL to retain 1.5 metre spatial resolution for hyperspectral Imagery. Calibration flights were conducted at the airport in Port Hardy, BC Canada. These flights were performed immediately after the completion of the project acquisition and consisted of two opposing flight lines along the runway and two perpendicular flight lines in relation to the runway. This pattern allows us to calibrate our system and solve for roll, pitch, and heading. The conditions required to complete the survey as originally intended to meet higher accuracy specifications never presented. Weather and local fog prevented the use of local airports and as such our flight baseline length were longer than anticipated; further, we were unable to position project control within the survey area. Due to these factors, the vertical accuracy of the survey should be considered at +/- 20cm relative and 1m absolute when compared against hard flat surfaces. Site Size: 477.22 km2 Projection: UTM Zone 9 Datum: NAD 83 Geoid: HT 2.0 Accuracy: 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 Due to the fact that the majority of the area is covered by overlapping flightlines, the point density averages closer to 2 pts/m2

  2. 2014 acquisition by UNBC Lidar Research Group: Flight - Aug. 7, 2014 - Flight was designed to cover four large gap areas in the 2012 Lidar as well and enhance NW Calvert Island Lidar results. Scanner Type: Riegl VQ-580 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

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.

For a full metadata report on Lidar acquisition please contact data@hakai.org

Access and Use

Licence: Appropriate credit must be given to Hakai Institute and the authors of the dataset.

Data and Resources

Dates

Metadata Created October 26, 2018, 22:48 (UTC)
Metadata Updated October 26, 2018, 22:48 (UTC)
Reference Date(s) 2016-04-09 (Creation)
2016-09-29 (Publication)
2016-09-29 (Revision)
Frequency of Update asNeeded
Metadata Date October 17, 2018, 21:59 (UTC)

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Dataset extent

Map data © OpenStreetMap contributors

Additional Info

Field Value
Contact Email data@hakai.org
encoding utf8
metadata-language eng
progress completed
resource-type dataset
Responsible Party Hakai Institute (Point of Contact, Processor)
spatial-reference-system 3857