UTM coordinates and height of survey control marks. The UTM coordinates are expressed in terms of both the Australian Geodetic Datum 1966 (AGD66) and the Geocentric Datum of Australia 1994 (GDA94). Height information is expressed relative to a number of datums. The quality of control mark coordinate information is expressed in terms of Class and Order. Attribute information may include the mark type, date established, access type and comments on condition. An abbreviated description of any visible target is included. Mark status indicates if control mark has been reported not found, or is destroyed but the reference marks still exist.

The source is primarily control surveys carried out by DPIPWE ILS Division, but does include information supplied by other agencies, professional surveyors and members of the public.

Position Accuracy: Varies depending on the Horizontal Order. For example, First Order GDA coordinates have an estimated accuracy of +/- 0.02m, the accuracy of Scaled coordinates will depend on the scale of the map used to determine them and could be +/- 500m. Attribute Accuracy: Class and order are assigned to both horizontal coordinates and heights in accordance with ICSM Special Publication 1 (SP1) Standards and Practices for Control Surveys (version 1.7). The accuracy of this attribute information is estimated to be 99%. Logical Consistency: N/A Completeness: The data set is essentially complete. Additional data is added when survey control marks that have been destroyed are replaced. Information and advice about the position, status or condition of existing marks is updated as it is received. It is anticipated survey control marks established by some municipal councils will be added. Additional: A summary of the datum realisations applied in Tasmania is available at www.dpipwe.tas.gov.au/land-tasmania/geospatial-infrastructure-surveying/geodetic-survey/coordinate-height-and-tide-datums-tasmania An explanation of terms used in the attribute information and summarised in the legend in the Layer tab of LISTmap is available and can be viewed at: http://surcom.dpiw.tas.gov.au/surcom/jsp/instructions_public.jsp#terms SP1 (version 1.7) was superseded in October 2013 by SP1 (version 2) which completed the transition from CLASS and ORDER to uncertainty as the basis for evaluating and expressing the quality of positions. The transition to the use of uncertainty to express the quality of the Tasmanian Survey Control records is planned but its implementation will depend on the datum modernisation process being considered by Australian jurisdictions in 2015. Any queries concerning uncertainty should be directed to the Custodian.