3.7 The LOCALITY Entity

The spatial relationship between the site of a groundwater_feature and the locality is described. This enables a groundwater_feature to be placed in context with the boundaries of geographic entities that may be natural (eg. drainage basins) or anthropogenic (eg. land tenure or electorates). The boundaries of a locality may be visible in the landscape (eg. ridges defining a drainage basin, fence lines defining a property boundary) or hidden (the boundaries of a 1:100,000 scale topographic map).

Assigning a groundwater_feature to a range of localities is particularly useful in data querying. It allows the selection of groundwater_features that are within a particular locality (eg. the BALLARAT SJ 54-7 1:250,000 topographic mapsheet, the parish of Windermere, the Lachlan River catchment, the electorate of Mundingburra). Many of the State or Territory groundwater databases already assign groundwater_features to localities such as mapsheets, the local cadastre and administrative regions (eg. shires, parishes, hundreds). With the spatial relationships between the groundwater _feature and the locality defined, the data user does not require direct access with the database that defines the locality. The locality entity also allows groundwater_features to be assigned to a readily expandable range of geographical features. The location on the land surface of a groundwater_feature can be described in the context of many localities.

Table 3.8 Attributes of the locality entity

The spatial relationship between a particular groundwater_feature defined by the feature_identifier and a particular geographical feature defined by the locality_identifier is described. The combination of feature_identifer and locality_number is the primary key for the locality entity.

The position of the groundwater_feature can be described using various types of localities, such as 1:100,000 scale mapsheets, postcode areas or state electorates. The localities of a particular type (eg. drainage basins) belong to a particular bibliographic_source (eg. AWRC, Division of National Mapping, 1975. Major Drainage Basins (Map 5) in Review of Australia's water resources. Department of Minerals and Energy) with defined data properties such as scale, accuracy, quality and currency. Wherever possible, localities should be defined by spatial data that have been standardised nationally. The development of such standards has been accelerated in recent years with the development of the Australian Spatial Data Infrastructure (ASDI). As part of this process, the Intergovernmental Committee on Surveying and Mapping (ICSM) are currently developing data models for geographic place names, street addresses, cadastral data and administrative boundaries. The Australian Survey and Land Information Group (AUSLIG) provide a national digital coverage of 1:250,000 scale topographic mapping in the form of the GEODATA TOPO-250K product. In the second series, the themes of hydrography, infrastructure, relief, vegetation and reserved areas are being developed. AUSLIG also provide a national coverage of postcode areas, river drainage basins and Commonwealth electoral divisions. Standard domains are provided in the data standards for such locality types as 1:100,000, 1:250,000 and 1:1,000,000 scale topographic maps, states and territories, and drainage basins.

The relationship, for instance, describes whether the groundwater_feature is within the boundaries of the locality. A feature can also be near a locality such as a local landmark or township; in this case the azimuth and distance parameters are used to define the spatial relationship further. A groundwater_feature can also be a component of a locality. This is the case for bores that are part of a designated bore field or a line of monitoring bores. The position of a groundwater_feature can also be described in terms of the regional hydraulic gradient (eg. down-gradient of an evaporative disposal basin).

The relationship between a feature and a locality is assigned by an organisation on a particular locality_date.

3.7.1 Examples of localities

The site of a groundwater_feature may be:

• within the state locality of New South Wales;
• within the WENTWORTH 1:100,000 mapsheet number 7229 (NATMAP National Topographic Map Series, 1977) locality;
• within the parish of Caboolture (Queensland Parish Directory, 1983) locality;
• within the property of ‘Hazelmere’ (CPS43787 in Queensland Digital Cadastral Database, 1998) locality; or
• about 1km north-west of the Rocket Lake (UFI AA00000237, AUSLIG TOPO-100K) locality.