The southeastern Tasmania marine contour map 1:25000 depicts marine habitats from Marion Bay [147 57, -42 44] to Second Lookout Point [146 52, -43 40] from the coastline to the 40metre depth contour. The contour intervals are at 2metres, 5metres, 10metres, 20metres, 30metres and 40metres. The dataset is intended to be used to fulfil coastal management objectives according to The Living Marine Resources Act 1995 and is not to be used for navigational purposes.

Depth and positional point data was captured using a Garmin 135 GPS unit coupled with a RACAL differential correction unit. The point dataset was checked for extraneous data, cleaned and converted to a coverage. The point coverage was then interpolated using ESRI ArcView Version 3.2 Spatial Analyst option to create a TIN (Triangular Irregular Network) surface. Using the create contours option in Spatial Analyst a contour coverage was generated from this TIN. The intervals were established at 2m, 5m, 10m, 20m, 30m, and 40m. The 1:25000 coastline was supplied by the Land Information Services Division of the Department of Primary Industry, Water and Environment Tasmania. Equipment employed to record and measure the data included [Furuno 600L colour sounder, Garmin 135 GPS map unit with a RACAL differential correction unit.] Areas were sampled following transects in from the 40metre contour line to the coastline. The sampling method resembled a zigzag pattern at 200m intervals. The GPS recorded depth and position regularly at 5second intervals to generate a point dataset of 200 000 points. Sampling effort was increased in areas that demonstrated complex habitat composition.

Position Accuracy: The accuracy of the GPS was assessed by recording at fixed points over extended time periods. It was found to vary by no more than 12meters over a three-hour period. Attribute Accuracy: Using a Garmin GPS Map 135 Unit depth and position data were simultaneously collected and downloaded to a data file. The accuracy of the sounder was assessed by measuring the depth of water at buoys of known depth and location. This was done at various speeds. It was found that the accuracy was to vary by no more than 20cm. Logical Consistency: All data has been checked for extraneous points. Completeness: The 1:25000 Contour Mapping Series has been completed for the south eastern section of Tasmanian waters from the coastline to the 40metre depth contour. Additional: Marine habitat mapping of the Bruny-bioregion for Marine Protected Planning. Sanderson et al. 2001 http://www.utas.edu.au/docs/tafi/TAFI_Homepage.html