Georeferencing

All data used in a GIS needs to be defined by a coordinate system and data used for a particular application must be georeferenced to the same coordinate system.

Ground truthing is generally used to locate remotely sensed data.

• For cadastral data sets parcel boundaries, locations of infrastructure and utilities features can be surveyed accurately using laser theodolites.
  
  
• Socio-economic and demographic information can be linked to cartographic zones with a particular spatial reference.
  
  
• Information from market research can be linked to post-codes to spatially locate the data.
  
  
• Natural resource information is normally recorded in terms of latitude and longitude.
  

	Summarising referencing
List the reasons why it is important to georeference the data you use in a GIS and identify how GPS can help.