Maps are produced from data collected over many years and from diverse sources, including satellite imagery, local councils and land holders, state mapping agencies, field investigations, commercial map producers, government agencies and the general public.
This data is held in a variety of databases with specific software used to extract and manipulate the data to produce maps. Mapping is a complex and specialised activity and Geoscience Australia provides much of this data for free or for a nominal cost, allowing other map producers and organisations to use the topographic data in their own projects.
We have approximately 130 Gigabytes of base topographic data. There are approximately 1000 datasets for the various themes and features that complete our mapping data repository, each with a specific purpose for incorporating into products as required. Data can be supplied in a variety of formats to end users, including printed maps and Geographic Information System (GIS) formats.
New and evolving data delivery methods are becoming available, including MapConnect our online topographic map download facility, and geo-referenced PDF digital maps.
Digital spatial data, or Geographic Information System (GIS) data, is a digital representation of the real world. Spatial objects such as points, lines and polygons are used to depict spatial features:
The spatial objects are linked to attributes that describe the features and phenomena that exist at those locations.
GEODATA is our range of digital data products designed specifically for use in geographic information systems (GIS). The following scales of topographic data are part of the GEODATA range: 1:100 000 for the ACT Region; 1:250 000; 1:2.5 million; 1:5 million; and 1:10 million.
While GEODATA are designed for use in GIS, for applications such as polygon overlay and network analysis, they are flexible enough to be transformed into other formats to allow their use in computer aided drafting (CAD) packages, non-graphic databases and spreadsheet applications.
All GEODATA products are:
Geoscience Australia began capturing digital map data in the early 1970s, primarily for map production purposes. The data has a structure and graphical accuracy well suited to the reproduction of maps at the same or smaller scales to the source material. However, the data may vary greatly in quality depending on the method of capture and digitising specifications in place at the time of capture. This data is best suited to graphical applications.
Products not complying with the GEODATA standard use the geometric objects of points and lines to provide map detail. Points are used to depict point map features or symbols, while lines are used to depict linear features such as roads and rivers or to delimit the boundaries of area features such as lakes and large buildings. The cartographic feature represented by the point or line is given by a feature code.
This map data is most suitable for use as a graphical backdrop but can be used for more sophisticated GIS applications after some restructuring by the user. Such products include the non-GEODATA 1:100 000 data and various thematic data.