When acquiring digital data from a supplier it is important to be aware of problems associated with differences in projections, scale and the description of attributes, these can cause problems with your own GIS requirements.

To check that the data characteristics are consistent with the application look at

• the currency of the data
  
• the length of record
  
• scale of the data
  
• georeferencing system used
  
• data collection technique and sampling strategy
  
• quality of the data
  
• data classification and interpolation method used
  
• size and shape of mapping units
  

(Burrough and McDonnell, 1998)

You should become familiar with the lists of national suppliers and Northern Territory suppliers.

	Researching suppliers
Which of the suppliers listed would be likely sources of vegetation, geological and species data for the 'Top End'? Look at the relevant web sites and identify How much it would cost Who you would need to talk to in order to acquire the data. Note the answers in your e-journal. Share your findings in the discussion forum.