Laser Airborne Depth Sounder (LADS) bathymetry data (Australian Hydrographic Office)

LADS is a swath sounding system that collects data in a grid 240 metre wide, with a sounding at approximately every 10 - 11 metres. During normal survey operations parallel LADS survey runs are flown at 200 metre intervals, resulting in a 40 metre overlap between runs. A LADS survey run will have 24 columns of sounding data, of which 22 are useable. The soundings in columns 1 and 24 are not used for hydrographic purposes. Data along a LADS run is divided up into "FRAMES". One frame equates to two seconds of LADS data, an area 240 metres wide and 150 metres long. Each row or swath of soundings within a frame is known as a "SCAN". There are 14 scans to a frame. Thus a frame can contain up to a theoretical maximum of 336 soundings (pulses of the laser) in 24 columns and 14 scans (14 x 24 = 336). However as soundings in columns 1 and 24 are not used, therefore the total number of soundings in a frame is 308. Consecutive frames of data do not overlap. The centre of each frame has a GPS position applied to it. All other soundings within that frame will have their position calculated from the central position of the frame. Each frame also has a frame correction; corresponding to the tidal reduction, which is applied to all soundings within that frame. LADS survey runs are typically planned to be around 45 nm in length, although this can be varied. A run of this length will typically contain 550 frames of useable data or 169400 possible soundings. On a typical LADS sortie with 4.5 hours on task it is possible to fly 10 of these runs, as well as conduct a navigation calibration and fly a benchmark run. This equates to approximately 1.69 million possible soundings or an area surveyed of 52 sq nm. The largest area ever surveyed in a single sortie was 88 Sqnm. The area surveyed per sortie increases marginally if the run lengths are increased but decreases drastically as run lengths are decreased, due to the lost time in turning between lines. Raw LADS data collected in the air is stored in binary form on Magneto Optical Disks. On returning to the ground the data is copied onto a single DAT tape, and is then automatically processed using the Ground Analysis Sub System (GASS) into a recognisable form. The available data covers the following survey areas: HI185: Flinders Passage HI193: Bunker Reef to Fairway Channel HI220: Cooks Passage to Trinity Opening HI221: Cape Weymouth to Blackwood Channel HI221_2: Fairway Channel (NW Extension) HI241: Hope Island to Lark Pass © Commonwealth of Australia (Australian Hydrographic Office).

Data collected during these periods: 07 Mar 1993 to 27 Apr 1996

Data Usage Constraints
  • Legal Use Limitation: Not to be used for navigation
  • Legal Access Constraint: license
  • Legal Use Constraint: license
  • Legal Other Constraint: Certain hydrographic information in this product is © Commonwealth Of Australia. Apart from the uses permitted to the licensee under the licence agreement, the information may not be copied, reproduced, translated or reduced to any electronic medium or machine readable form, in whole or part, without the prior written consent of the Australian Hydrographic Office. These data were purchased by the Australian Institute of Marine Science under licence from the Australian Hydrographic Office and are available for AIMS internal use only. This material has been supplied for research purposes only.
  • Security Classification: unclassified
Data Cite
  • Hydrographic Service RAN - Australian Hydrographic Office. 2017, Laser Airborne Depth Sounder (LADS) bathymetry data (Australian Hydrographic Office), http://data.aims.gov.au/metadataviewer/faces/view.xhtml?uuid=a82ca1a3-7c67-4713-873f-a7fc74744d56, accessed 21/10/2017
Metadata Usage Constraints
  • Legal Other Constraint: All users of AIMS metadata must acknowledge the source of the material in the following manner: "Metadata was sourced from the Australian Institute of Marine Science (AIMS)." Format for citation of metadata sourced from Australian Institute of Marine Science (AIMS) in a list of references is as follows: "Australian Institute of Marine Science. [year-of-metadata-download], [Title], [metadata-access-URL], accessed [date-of-access]".
  • Security Classification: unclassified
Credits
Hydrographic Service RAN - Australian Hydrographic Office
Thumbnail Image: Australian Hydrographic Office
Cited Responsible Party List
Publisher
Hydrographic Service RAN - Australian Hydrographic Office
Point Of Contact List
Point Of Contact
Data Manager, AIMS Data Centre Australian Institute of Marine Science (AIMS) adc@aims.gov.au