Title

Western Port Depth Contours at 1:25,000 

Alternate title

BATHYMETRY_WESTERN_PORT_ARC 

Purpose

BATHYMETRY_WESTERN_PORT_ARC is a 1:25,000 layer used for depth analysis. Ecological research requires the type of detailed information within the BATHYMETRY_WESTERN_PORT_ARC layer relating to the nature of the sea bed. Depth models have wide ranging uses in the fisheries management, development of aquaculture and ecological research. The depth information within this layer should not be used for navigation purposes. 

Supplemental Information

History: The surveys from which the original depth contour charts were produced began in September 1974 and ended in April 1985. The digital capture of these charts for GIS commenced in December 1999 and was completed in February 2000. This layer replaced WP_BATH_25 in March 2010 Relationship to other Datasets: The BATHYMETRY_WESTERN_PORT_ARC layer draws on information stored within the SHORE25 and HYDRO25 layers. The coastline is subject to change especially in areas subject to erosion or mass movement of coastal sediments. Current Design Issues: Bathymetric information is initially collected as point features or spot depths. Isobaths are interpreted either by visual manual methods or by automated techniques. As more data becomes available the positional accuracy of isobaths should be revised. Each acquisition of depth information needs to be documented and assessed before it is incorporated in the layer. Future Design Issues: This layer is a base line data set and future design considerations will be limited. Related Documents: None 

Status

Completed  

Horizontal Accuracy

25m  

Code

4283 

Maintenance and update frequency

Not planned  

Topic category

• Oceans

Use limitation

http://www.data.vic.gov.au/ NOTE: The depth information contained within this layer should not be used for navigational purposes. 

Classification

Unclassified  

Statement

Dataset Source: Data was digitised from Victorian Channels Authority charts (formerly Ports and Harbours). The depth contour charts digitised to create the layer are listed below. The scale for all of these charts is 1:25,000 WP425-3023. Eastern Entrance to Corinella. Surveyed Nov 1977-Oct 1984 WP426-3024. French Island East - East Arm to Tooradin. Surveyed Nov 1977-March 1983 WP427-3025. North Arm - Hanns Inlet to Blind Bight. Surveyed Sept 1974-April 1985 WP428-3026. Western Entrance to Sandy Point. Surveyed Sept 1974-Aug 1984 For all of these charts, the composites are derived from the 1:10,000 series, Ports and Harbours, the shore detail is derived from the 1:25,000 series, Lands Department, and contours are in metres and are to chart datum, which is 1.6m below the Australian Height Datum (AHD) Dataset Originality: Primary & Derived 

Description

Collection Method: Hydrographic survey vessels, visual interpretation of depth points by draftsman 

Description

Contours were digitised directly from all the charts. The digitised lines were then appended and the depth contours edited at the point where they overlapped. 

Classification

Unclassified  

Attribute Quality

Comments

All attributes have been checked by DPI 

Positional Accuracy

Comments

Horizontal and Vertical accuracy have not been determined. The depth information within this layer should not be used for navigation purposes. 

Conceptual Consistency

Comments

Attributes have been checked by DPI 

Missing Data

Comments

Layer is complete for Western Port. Note however, that contours do not exist for the area west and south west of Middle Bank which has been inadequately surveyed. 

Excess Data