At a time when information and data are becoming an integral part of every organization, people have realized that paper records, books, and journals are not as handy or safe as CD-ROMs. Information must be stored in such media that the storage is safe and the retrieval is quick. The age of Data Digitisation has begun.
Digitisation is the process by which physical or manual records such as text, images, video, and audio are converted into digital forms. This is of paramount importance when projects need directions based on already established facilities and the implementing agency needs to find the scope for expansion.
Digitised data offers the following benefits: Long term preservation of documents, orderly archiving of documents, easy & customized access to information, easy information dissemination through images & text, CD-ROMs, internet, intranets, and extranets
The digitising applications are rapidly evolving around the world as computers are becoming an essential office and home equipment. Libraries, Corporate, Government, Armed Forces, Museums and Educational and Research organisations are looking at various efficient storage and distribution applications.
By linking local markets through digitization, technology has created the global market. It has flattened the hierarchy of business by cutting out inefficient layers and middleman, so that the producer can reach the consumer directly. It has also "empowered" the individual consumer and producer by increasing his access to information, his capacity to process that information and his capacity to reach out directly to other consumers and producers almost without restraint.
Some application areas of the digital technology are as follows:
- Research Journals and Conference Papers
- Annual reports and price list
- Database archiving
- Movies, Sounds and High quality image preservation
- Electronic Catalogues & Brochures
- Product/Service Training Manuals
- Geographical Information System.
Kinds of Data Digitisation
Manual Digitisation : Manual digitisation is carried out on a digitisation table which looks like a drafting table containing a mouse-like device with crosshairs called a ‘puck’. The digitisation table works in a sophisticated manner similar to a tracing device electronically recording the positions of points and lines. It is embedded with a mesh of fine wires forming a grid like surface and this is draped or covered with some smooth surface. On this surface is mounted the map or the imagery which is to be digitised. The map is then taped to the surface which prevents the map from any types of movement. The puck is placed on the map and the electronics of the system working on electrostatic system in conjunction with the wire grid picks the signals from the puck and converts the position of the puck into a digital signal. This signal is processed by a software in the computer converting the signal gets into x,y co-ordinates depicting the position of the puck. Thus the features on the map or imagery are literally traced out by the puck. A very important aspect in this regard is the correct choice of the co-ordinate system referred to as projection system, so that the features present on the curved surface of the earth is projected properly on to a flat map. Many new digitisation softwares support a variety of projection systems but while working with a paper map, the projection used by the base map should be known and the software should be set accordingly.
Heads-Up Digitisation : Another very commonly used method of digitisation is the on-screen digitisation or ‘heads-up digitisation’. This method of digitisation is very similar to manual digitisation except that the base map or image is already in a digital raster form i.e. in the form of a digital image. It is known as ‘heads-up digitisation’ because the attention of the user is focussed up on the computer screen and not on a digitisation tablet. The main idea in this type of digitisation is to convert this digital image into a form usable in the GIS environment i.e. in a form such that each feature on the map has a geographic co-ordinate associated with it. In this method, the first step is to convert the paper maps or imageries into a digital image. This is accomplished using a scanner. A scanner automatically captures map features, text, and symbols in the map as individual cells, or pixels, and produces an automated digital image in raster format. But this raster image lacks any geographic information which has to be inputted manually. For this, the digital image is displayed on the screen and zoomed to a comfortable level such that all the features on the digital images can be easily traced out on the screen itself to create new layers or themes. For this method also choosing the proper projection is necessary. In a similar manner, control points with known geographic locations are identified and marked based on which the geographic co-ordinates of all the features in the map is known. Another improvement in on-screen digitisation is the interactive tracing method which automates the line tracing method in such a way that it traces one line at a time automatically under the guidance of the operator.