The easement dataset shows the extents of the gazetted easement granted to Tasmanian Gas Pipeline (TGP) Pty Ltd within which the high pressure TGP and associated utilities and facilities are located. No inference should be made as to the location of the gas pipeline itself based on the easement location and boundaries. The pipeline planning corridor (PPC) dataset shows the extents of the planning corridor defined within the Gas Pipelines Act 2000 and Gas Act 2000. The purpose of the PPC is to notify TGP of all developments in the vicinity of the pipeline so as to inform councils on pipeline safety and the appropriateness of proposed developments when deciding on such applications.

Easement layer Lineage description: Source Data: Data is sourced from the files that were used by Lester Franks Survey and Geographic (LFS&G) Pty Ltd to create the Survey Plans and register the easement. Master data source is the post-backfill survey files (eg. SPE_0-22_pbf.dwg) created by LFSG. Processing Steps: (1) 8 January 2001: Compiled from source data provided Project Draftsperson during Engineering Design. (4) Updated access/services easement added near Wynyard MLV. Jan 2004 (2) 13 March, 2002: Updated from source data provided Project Draftsperson during Engineering design taking into account route changes and groundbed design. (3) 27 March 2003: Updated to as-built with the registered easement compiled by Lester Franks Survey and Geographic. (4) November 2007: Migrated to ArcSDE APDM data Model. Lineage statement: Position Accuracy: The easement is a best fit taking into account the location of the as-built pipeline, and adjacent property boundaries. The easement was snapped to property boundaries (survey accurate) where it was co-incident with the boundary. Drafting standards have ensured that each side of the easement is parallel at a consistent width whereever applicable Attribute Accuracy: The LAYER field defines the broad easement types. "Gas Supply Easement" is the main TGP easement surrounding the gas pipeline. "Groundbed easement" is the easement surrounding the groundbed cable and the anode bed at the end of the cable. "Access Easements" exist where one in required for ROW access. "Access and Service Easement" exist where the easement has dual purposes of ROW/Facility access as well as servicing groundbeds, electrical cables or other services. "Compiled Property Boundaries" exist where land has been acquired for the TGP facilities. Logical Consistency: The project GIS (ArcInfo) was used to do topological consistency check to detect flaws in the spatial data structure and to flag them as errors. This check insures that all lines are cleaned for undershoots and overshoots, nodes are formed at the intersection of lines and all lines are attributed. Completeness: Complete PPC layer Lineage description: Survey supplied pipe centreline from LFS&G. Pipe centreline was generated from surveyed weld and bend locations. (Please refer to As Built Pipeline for more details). All processing completed in ArcInfo. Pseudo nodes removed, centreline generalised to 25m, copied arcs parallel appropriate distance based on the pipeline diameter and analysed against buffered centreline. Where differences occurred the nominated corridor was altered to align with buffer. Rounded corners were removed to allow future PI interpretation if necessary. Corridor is based on pipe centreline buffered to a distance equal to the pipe diameter Lineage statement: Position Accuracy: At extreme bends a difference of 50m (to the actual Planning Corridor) can occur. More than 95% of linework is within 10m of true buffered distance as calculated by buffering the detailed as-built pipeline form TGP, SPE and NPE by 355.6m, 219.1m and 168.3m respectively (the pipeline diameter expressed as metres). Attribute Accuracy: N/A Logical Consistency: One polygon represents entire corridor. Completeness: Data coverage is complete for all areas.