Digitisation results in tracing the map or other analogue feature into digital form in which each feature has a proper locational identity. To ensure that each point is displayed in its original location a few steps have to be maintained while digitising. This helps in defining the position of the map with respect to the table. This ensures that if the map is displaced, then the new corners are to be only digitised and no other changes are to be made within the map area. The next and the most important step is to register and define several control points with a minimum of four points.
Control points refer to points on the map whose real geographic co-ordinates are known.
This is required for transforming the digital map into a similar projection as the original map such that each feature on the digital map displays its correct geographic location. After these preliminary steps, the features on the map are traced out using the puck in the form of points, lines and polygons with each feature having the correct geographic location. This site is best viewed with Internet Explorer 4.0 and above, at display settings of 800X600 pixels GISdevelopment.net. All rights reserved. GISdevelopment.net does not necessarily subscribe to the views expressed in this site.