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Field Calibration/Validation Data » Field Data Collection Protocols » Terrestrial Laser Scanner Protocol Web Page

Terrestrial Laser Scanner Protocol Web Page

Last modified by John Armston on 2014/07/09 14:25

The following protocol document provides a brief summary of the collection process for Terrestrial Laser Scanner (TLS) plots.

Plots

Plot selection process

Each 1 ha plot is a small homogenous area representative of a particular landscape. As many sites as possible are selected within the super site to ensure sampling of the major of landscapes present (determined by landform, vegetation, land surface, soil and other land features).  Capturing the variability at the site should also be a priority. Site selection can be informed by viewing satellite imagery or aerial photography.

 

The following points need to considered when locating sites:

  • Plot areas should have "homogeneity of heterogeneity" in canopy structure and landform;
  • To minimize edge effects, the edge of a site should be at least 100 metres from roads, power lines or other features not characteristic of the plot.

 

Description of plot layout

tls_sampling_protocols.png

Figure 1. TLS sampling designs.

 

Basic data required

The following data must be recorded for each plot, for data management purposes.

  • Geographic coordinates (easting, northing,zone) at plot centre
  • Operators: who collected the data
  • Date: consistent format (dd/mm/yyyy)
  • Time: consistent format (hh:mm)
  • Plot name: name of specific plot

Data collection process

Field equipment checklist

  • Terrestrial laser scanner (TLS)
  • TLS tilt-mount (for Riegl instruments)
  • Surveying tripod
  • Reflector targets
  • Differential GPS
  • 3 x 100 m measuring tapes
  • Stake or star picket
  • Hammer
  • Compass
  • Field sheets and clipboard
  • Electronic site forms and notebook computer (optional)

 

Process

1.    Locate scan positions

  • Lay out tapes based on the sampling protocol. These also assist in later when laying our reflector targets.
  • The scanned must be placed in a gap to operate. Once the nominal scan position has been located, there must be no material within 1.5 m range of the scanner due to the minimum range of the Riegl VZ400 instrument and to avoid major occlusion effects. If necessary, the scan position should be moved the minimum distance required, and the bearing and distance from the nominal position recorded.

2.    Lay out reflector targets

  • Full survey control
  • Tilt-scan overlap

3.    Acquire scans

  • Scanner height above ground (1.6 m)
  • 0 degree tilt scan
  • 90 degree tilt scan

Figure 2. Riegl VZ400 in the 0 degree (left) and 90 degree (right) tilt positions.

4.    Collect site metadata

  • ODK form

Data Recording and Storage

Recording of data in field

Data in the field will either be directly entered into specially prepared ODK forms, or into field sheets and then transcribed later.  

 

Database storage

Data is stored in the AusCover PostGIS database, located on the AusCover UQ server. Data is downloadable from the AusCover spatial portal

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Created by John Armston on 2014/03/07 10:18

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