TASVEG is a Tasmania-wide vegetation map produced by the Tasmanian Vegetation Monitoring and Mapping Program (TVMMP). TASVEG comprises 157 mapping units captured at a nominal scale of 1:25,000. TASVEG is continually revised and updated via photographic and satellite image interpretation and is verified in the field where possible. This version (4.0) represents the fourth major release of the TASVEG layer since 2004. TASVEG mapping is indicative only. Whilst extensive checks are applied to release versions of TASVEG, confirming the presence or otherwise of TASVEG communities requires field validation by a qualified practitioner.

The first version of TASVEG (TASVEG 1.0) was released in 2004. The initial TASVEG release incorporated existing information from the Regional Forest Agreement mapping program and from the World Heritage Area (WHA) mapping program, with remaining areas of the state mapped by the TVMMP. Since TASVEG 1.0 there have been three minor versions released; 1.1 and 1.2 released in 2005 and 1.3 released in 2007. Two major versions have been released since TASVEG 1.0, these were 2.0 in 2009 and 3.0 in 2013. Each new version of TASVEG has been accompanied by a statement indicating which new mapping data has been incorporated since the last release. Photographic interpretation (PI) of DPIPWE's most current aerial photography is the primary method of data collection for TASVEG updates, with field verification of representative polygons undertaken where practicable. Some aerial photography is analysed stereoscopically where feasible, but the majority of imagery is analysed orthographically within a Geographic Information System. Imagery is interpreted by vegetation scientists within DPIPWE who directly edit a master version of the TASVEG layer. Ancillary information such as such as geology maps, species records from the Natural Values Atlas, elevation data, hydrographic information and ecology texts are consulted to assist in the accurate typing of vegetation during PI. TASVEG also incorporates updated mapping supplied by external stakeholders where the veracity of such data can be confirmed.

Position Accuracy: TASVEG data is predominately captured via on-screen digitising at a nominal scale of 1:25,000 with generalisation of vegetation boundaries necessary for conceptual representation. The aerial photography primarily used in the mapping process is orthorectified and registered to between +/-2.5m and +/-17.5m of true position at the 90% confidence level. Horizontal accuracy of orthophoto data varies according to imagery age and source, which can be obtained from the State Aerial Photo Index. Attribute Accuracy: TASVEG uses 157 distinct mapping units. The forest vegetation mapping units (which primarily originate from the RFA forest vegetation communities mapping) are largely based on the dominant canopy layer, with one or more species consistently present. A smaller selection of forest vegetation communities are defined by the combination of dominant canopy species and known understory type. Some forest mapping units are also characterised by geology, topographic features, altitude or the height of dominant trees. Non-forest vegetation community mapping units may be characterised by geology, environmental and topographic features and dominant species. Field verification of data is strategic, with priority given to rare or threatened communities, and communities where remote identification is less reliable. WHA mapping was largely derived from PI and verified in the field. Apart from the presence or otherwise of field verification, attribute reliability can be inferred from the mapping source date and source type, and from the source interpretability rating scale. Logical Consistency: TASVEG 4.0 has been quality assured for topological correctness including the omission of overlaps. Checking of attribute values has been performed to ensure all attributes comply with the valid values set out in the TASVEG editing business rules. Preliminary logical consistency checking has been performed on suspicious locations of tagged communities to correct gross errors in geographical distribution. Completeness: The TASVEG dataset covers the entire State including its larger islands and a number of smaller offshore islands. This dataset is complete for the purpose of the current TASVEG release (version 4.0). The data is suited for use as a statewide and regional overview, for reporting purposes and for determining the probable location of vegetation communities. Tasks requiring more current or precise vegetation boundaries should seek alternate data sources or undertake field verification.