History of Digital Cadastral Databases (DCDB) Important Date 1992 – Meeting of the Surveyors- General The discussion included - Reasons for DCDBs - Methods to compile DCDBs - Computing capability required to support DCDBs
Main Reason DCDBs were becoming important “The processes for updating and upgrading DCDBs are gaining considerable attention world-wide as GIS users recognise the importance of the currency, quality and content of the DCDB that underpins their GIS application.” (Effenburg, Williamson, 1997)
The uses of the DCDB The uses of the DCDB were growing rapidly, these included; Environmental monitoring and mapping Asset management – local government, utilities etc Defence and security Mining and exploration Forestry Management of road Mapping items of interest Spatial analysis etc
Creation of DCDB and associated problems DCDBs are produced by digitising survey plans Importing sections of data from LGA, Utilities Challenges with DCDBs Digitising produces errors Errors compound as DCDB grow from the starting point Updating New surveys need to be rubber sheeted into existing DCDB structure, degraded new surveys
Challenges faced with early DCDBs Accuracy Managing Assets
What changed? Late 1990’s the computing power of personal computers increased over 100 times Global Satellite Navigation Systems became a reality
The change from DCDB to NCDB Numerical Cadastral Database (NCDB) NCDB is based on Geodetic Network Links the Survey control to the Cadastre Increased Spatial accuracy
Other benefits of NCDB Create associations between spatial and non spatial data called topologies Modify either spatial or non spatial without impacting the topologies GIS Users have access to a spatially accurate base layers that can be updated more easily Surveyors have the ability to obtain two way transfer of information into and from the GIS Supports dynamic datums
Direct link between surveyors and GIS Surveyors capture data Present in plan format (media or digital) Plan data entered in a database Parcel Fabric is updated with real survey measurement This is where the Survey plan can disappear
Current installations in Australia South Australia 20% completed, using Esri’s Parcel Editor NT have a complete NCDB with legislation to enable titles to be legally represented by coordinates NSW is using a partial Parcel Editor solution Victoria, need funding for their business case Queensland about to begin a business case ACT and WA keeping a watching brief
Tasmanian Spatial Information Framework 2008 Tasmania determined to create Spatial Information Framework (SIF) Cadastre considered important component to SIF 2011 received funding for SIF NCDB Enablement tender released May 2012 August 2012 Esri Australia, Geodata Australia and Applied Land Systems as a consortium awarded tender September 2012 commenced Stage 1 of project Funding to June 2013.
Tasmanian Spatial Environment The Land Information System Tasmania (LIST) established in late 1990’s – State SDI DCDB built from mix of 1:25,000 and 1:5,000 mapping data Includes spatial representation of a range of interests Supplemented with updates and upgrades Titles Office introduced semi-digital plan examination (PC Plans) Database not structured to record survey information ESRI/Oracle/SDE based.
Tasmanian NCDB Enablement Project Esri’s Parcel Editor capability chosen Most existing functionality to be retained Two stages proposed: - 1. Pilot over Launceston Municipality (40,000 parcels) - 2. Enable database and upload existing State data Stage 1 report by February 2013 Stage 2 optional depending on outcomes of pilot Initial data load by reverse engineering Post project - progressive conversion to survey data input based on updates and project upgrades.
Activities undertaken as part of Stage 1 Review of current environment New Cadastral Data Model Create pilot database from this model Adapt US Local Government model Load pilot area data into the two databases Develop data management workflows Test updates and upgrades Demonstrate required functionality and resolve issues Report on pilot and recommendations for Stage 2.
Stage 1 issues Complex array of owner and administrative interests Data loading from DCDB and multiple overlaps Features to include in fabric or retain in GIS Semantics of US LG model and varied attributes Specific functional requirements reflect current processes Need to separate tasks in pilot from compliance issues Time required to complete tender, finalise contract, agree on approach Scope change due to new software version 10.1 Reliance on bespoke ArcEdit user interface.
In Summary Cadastre still an important base layer Technology is providing the ability to better manage the cadastre Creates opportunities for Surveyors to embrace this technology and become spatial data managers again