Types of Reference systems

Spatial reference systems refer to a method for providing a framework for allocating position to objects.

In surveying two reference systems are utilised.

1. Non-coordinate based, and
2. Coordinate based.

The reference from the real world to these systems is made by surveyors using known points...

Monuments - the link to the real world: A series of survey marks become the definition of the system on the ground, example of which include...

• Trig stations
• SSMs - standard survey marks
• Bench Marks (BM) - for height references

By survey connection to these monuments we can integrate our data into a common coordinate system.

Changing practices

Traditionally the monuments have been placed on hill tops for intervisibility between points, but with GPS surveying techniques, these visibilty constraints may not apply.

Details of the marks are available through state and federal mapping agencies

• DOLA (Western Australia)
  • Geodetic Online Access (GOLA) facility
• Geoscience Australia
  • Geodetic data