The initial capture of the DCDB data began in 1988 by digitising the best available cadastral mapping at a range of scales and accuracies in accordance with the National Mapping Council of Australia, Standards of Map Accuracy (1975). The data set was broken down into map tiles or partitions which were based on the 1:25 000, 1:50 000, 1:100 000 and 1:250 000 map sheet breakdown of the State. In Read More » more dense urban areas, the partitions were further broken down into quadrants until each quadrant contained no more than 8-10 000 parcels each. The position of the feature instance will be within 0.5 mm at map scale for 90% of the well-defined points. That is, based on the scale of the source documents, the positional accuracy of the cadastral points will be; 1:500 = 0.25m, 1:2000 = 1m, 1:4000 = 2m, 1:25000 = 12.5m, 1:50000 = 25m and 1:100000 = 50m. The source of the data was recorded in the metadata for each map tile or partition. During the initial capture phase, any existing control was identified from the Survey Control Database, standard cadastral and topographic mapping control. This control was used during the digitisation process to geo-reference the data. Additional control was incorporated as necessary to maximise spatial accuracy. This initial capture process was completed in 1994. Beginning in 2005, the data was migrated to an ESRI-based geodatabase. The database is constantly maintained or updated on a daily basis from registered plans (including E-Plan), registration of land transactions in NSW and changes in administrative boundaries as gazetted. The data is up-to-date to within 10 working days from when a plan is lodged at LPI NSW. Data is also sourced from Crown Lands, the Office of Environment and Heritage, the Aboriginal Land Council, Livestock Health and Pest Authority, the Electoral Commission and the Department of Trade and Investment. The LPI DCDB upgrade program commenced in 2007 and is ongoing, improving the spatial accuracy of different feature classes. In 2007 an upgrade program began to improve the positional and topological consistency of the DCDB. Three separate methods are used to upgrade the DCDB. Conflation moves the DCDB to match another data source, for example, cadastre supplied by Local Councils or Utilities. Dimensioning uses bearings and distances stored in the DCDB to run a least squares adjustment. Block shifting moves the cadastre to match an image. The positional accuracy of the upgraded cadastre ranges from less than 5m from true position to less than 0.2m from true position depending on the method used. Data quality in both Cadastral Maintenance and Cadastral Upgrade is assured through specification compliance and data topology rules. The client delivery database is automatically updated each evening with the changes that occurred that day in the maintenance environment. LPI uses a number of specialist processes for manual manipulation, transformation and reformatting to meet client needs, automatic transformation and reformatting for product delivery, and automated manipulation for the rendering of LPI spatial data in purpose built web services. For the complete data model and definitions for all attributes, please refer to the DCDB Data Dictionary at http://www.lpi.nsw.gov.au/__data/assets/pdf_file/0003/60933/NSW_Cadastral_Data_Dictionary.pdf « Less