Updated:   11 December 2006

2.2.2 Roads Vs Linear Features

2.2.2.4 Example 4

Location of Example: 152o19'30" East, 24o56'35" South
Distinctive Characteristics:
  • Drains/Canals can be differentiated from Roads as they do not provide connectivity to the existing road network.
  • If the Drain/Canal is completely dry it will appear lighter, similar to the surrounding soil and vegetation. The the edges will often appear much lighter, due to the excavated soil from construction.
  • Drains generally start at a water source and can end at a Reservoir, Water Tank or Sea.
  • Drains follow the topography of the land whereas roads may traverse hills and valleys.
  • In Figure 2.2.2.4a the canals appear as dark blue linear bodies when filled with water.
  • The use of mulitspectral imagery band combinations can aid in the interpretation and differentiation of water.
Regional Considerations:
  • In areas where there is irrigated crop farming Canals/Drains appear as regular structured networks which show a water flow hierarchy diminishing from source. They are often aligned with paddocks and have access tracks or roads running parallel to them.
Figure: 2.2.2.4 Representation of Canals.

Figure: 2.2.2.4a Orthophotography 40cm RGB=123 Figure: 2.2.2.4b SPOT Pseudo-natural 2.5m

Unless otherwise noted, all Geoscience Australia material on this website is licensed under the Creative Commons Attribution 3.0 Australia Licence.