|| The allowable error in attribute accuracy ranges between a 1% (new data additions) to 5% (pre-PIP maintained contract data). For this project, attribute accuracy is a measure of the degree to which attribute values of address points agree with the information on the source material.
Geocodes within Vicmap Address are classified as 'BB' accuracy, ie, 90% of well-defined features are within 1mm, at plot scale, of their true position, eg, 1:500 equates to +/-0.5m and 1:25,000 to +/-25m. Anecdotal evidence suggests that the spatial accuracy of the major part of the dataset, at all scales, is frequently better than BB.
Address points may vary in chosen geocode location :-
- Rural Adddresses with a RRN - If property access captured, the address point varies from 1 to 50 metres back from the property road frontage. If the access to the property is from a road not abutting the property or through an adjacent property, the address point will be located outside the property and a 'outside_property' flag is set.
If has been no access point location captured, the address point will be at the property centroid.
- Rural addresses with no RRN - The address point will be at the property centroid.
centroidnumberWhere a rural address access point is external to the property (eg end of a shared access track, a separate 'outside_property' flag is set.
- Urban addresses in Metropolitan Melbourne - 8 metres back from centre of the property road frontage
- Urban addresses in rural Victoria - Limited number 8 metres back from centre of the property road frontage, with the remainder at the property centroid.
It is envisaged that all address points in rural Victoria, apart from RNN's, will be located 8 metres back from centre of the relevant property road frontage by mid 2008.