What is 'Embedded GIS'? So far we have looked at geographic knowledge as something to be handled separately in an environment we call as the GIS. However, this leads to a dead end. For example how do we make geographical information available in the form of directions to a destination? Can a GIS 'read' a map and give directions in lay terms? The answer is yes and the corresponding enabling technology is embedding the GIS in the application and device. We can identify the following approaches to embedding technology.
This is perhaps the oldest technique of embedding and very well developed. All GIS software provides customisation tools to automate GIS functions through scripts. These could also include screen design tools to construct menus to enable a visual interface. Examples of such applications are many. In India the NRIS system uses embedded application modules to enable land and water management. The figure shows a typical interactive menu used in Natural Resources Information System (NRIS). The GIS and query functionalities are hidden behind the visual menu system which enables the user to interact with the system and invoke the query functions without knowing the GIS commands.  Fig 2 Vehicle tracking system The user is a subject expert - in this case a land use planner. The GIS expert acts as a mediator in absentia through the scripts and menu he has designed based on his understanding of the end users requirement. Apart from query, this kind of embedding can also be used to realise expert systems where the expert knowledge is embedded in programmes which can be called in the framework of the GIS. These programmes can be written in programming languages like C++ or can be invoked from another software package like an AI or Neural Network package. GIS embedded in applications The most common example of this kind of embedding is Web GIS. The web browser is used as the interface and HTML, XML and XML extensions are used to serve up GIS content. The example shows a web GIS interface developed for NRIS using Java servlets. Web enabling also allows other facilities like language transliteration as well as non-English menu items. The background GIS operates in English and the GIS expert provides the necessary translations. The transliteration is provided using special purpose firmware. These applications are fairly simple. However, by adding elements of GPS and communications a very powerful embedded application can be developed. These applications fall under the category of telegeoprocessing. Vehicle tracking systems have been developed using these technologies. The illustration shows a system developed by the Indian Space Research Organisation consisting of a vehicle mounted GPS receiver attached to a satellite transmitter. The transmitter is programmed to transmit the GPS readings at regular intervals. The INSAT MSS transponder relays the signals to a base station which decodes the position information and plots the position on a map. The map is web enabled and a user with a simple browser can access the information. This system has been used to monitor fishing vessels in the extended economic zone.  Fig 3 Interactive menue of Natural Resources Information Systems |