Shipwreck Databases Western Australian Museum

ArcView How to do it Manual No. 1: Georeferencing for Beginners

Author/s J.N. Green

Year of publication 2006

Report Number: 219

What is georeferencing?
A Geographical Information Systems (GIS) is a system for creating, storing, analysing and managing spatial data and associated attributes. In a GIS variety of graphical information can be displayed in form that allows the geographical coordinates of a particular point to be determined. In GIS, georeferencing is the process of scaling, rotating, translating and deskewing graphical information, particularly raster images, to match the geographical coordinate system.

An ordinary raster image is made up of pixels that have no particular size. By georeferencing, each individual pixel is give a particular coordinate corresponding to the point on the ground that it represents. Georeferenced images can be placed in layers on a GIS and used to locate positions on the ground.

What can you georeference?
Any map, plan, aerial photograph, satellite image that has know features that can be identified and their coordinates determined. You can even georeference semi-oblique photographs. Georeferencing can only be used for raster images. All image files used here are available on a CD for you to play with.