Abstract

Vertical height datums are necessary as a reference for height measurements over the Earth. However the choice of reference is dependant on the purpose for the height data. For terrestrial users (especially on the coast), heights above a Mean Sea Level (MSL) are desired, whilst marine uses that depend on under keel clearance, prefer a low water tidal datum. The result of these preferences has produced two different types of height datum in Australia. Topography heights are referenced to the Australian Height Datum (AHD), Roelse (1975), and bathymetry heights are referenced to Chart Datum (CD) or Lowest Astronomical Tide (LAT), calculated through a tidal observation. Both are not directly compatible with satellite based data in ellipsoidal heights, which span the land/sea interface. Users of these data sets are increasingly aware of difficulties in joining these adjacent datasets, primarily a result of datum disparities. The focus of the research in this report is to reconcile the various bathymetry datums to allow joining of bathymetry datasets. A methodology has been presented to calculate uncertainty for short span observation MSL's relative to a long term reference epoch. This will increase the number of available MSL observations around the coast, which will aid in the creation of an ellipsoidal MSL surface with uncertainties. Despite their inclusion in the original project scope, methodologies for computing uncertainties of the Lowest Astronomical Tide (LAT) and Highest Astronomical Tide (HAT) tidal planes have not been developed. Several alternative options for high water and low water tidal planes with associated uncertainties to define the intertidal zone about MSL in Australia will be presented for consideration.
Google map showing geographic bounding box with values North bound East bound West bound South bound
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Product Type/Sub Type

nonGeographicDataset - GA Publication - Report

Constraints

license
Creative Commons Attribution 3.0 Australia Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

2010

Product Type

nonGeographicDataset

Topic Category

geoscientificInformation

Keywords

GA Publication
Report
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Lineage

Unknown

Digital Transfer Options

onLine

DISTRIBUTION Format

pdf

Distributor

Role
distributor
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address

Metadata File Identifier

a05f7892-f8de-7506-e044-00144fdd4fa6

Metadata Standard Name

ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata

Metadata Standard Version

1.1

Metadata Date Stamp

2010-06-23

METADATA SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
For information on acquiring this product,
please contact the Geoscience Australia Sales Centre via:

fax:
+61 2 6249 9960; or
phone:
1800 800 173 (within Australia);
 
+61 2 6249 9966 (outside Australia).

Please note that support hours are 9 am to 5 pm weekdays