Low-cost internet/intranet enabled graphics viewer for GIS applications
D. M. Bedekar, S. M. Kharad, and Y. T. Pokharkar
L&T Information Technology Ltd., Plot 200,
Shil - Mahape Road Navi Mumbai, 400 701
The costs associated with the implementation of a GIS are often perceived as prohibitive. This is particularly true of small and medium enterprises, which operate under tight budgetary constraints. The paper proposes a technical solution, which can help to mitigate the problem and enable the organization to derive the benefits of implementing a GIS. The paper describes the development of a low-cost Internet enabled graphics viewer, which has been successfully implemented in an intranet-enabled GIS Application.
Network capability of current Internet GIS applications
The Internet has emerged to new heights within the last few years especially in developing countries. Also it is inexpensive and ubiquitous and renders "information like water". This makes it a perfect vehicle for carrying the GIS to the users across the globe. Current version of HTTP protocol does not support direct transfer of vector data type, which most of the GIS applications require. Hence the Internet users are not able to analyze and display vector data. As a result, GIS applications require:
What LTGIS Tool can do for GIS applications on the Internet/Intranet?
The heavy network traffic caused by frequent data transmission in existing Internet-enabled GIS systems, served as a catalyst to developed a new solution, which will enable users to download objects from the network GIS server to their local machines and make use of them locally. This will solve the problem of data transfer.
The LTGIS Tool - A Internet enabled GIS
Languages: Microsoft Visual Basic 6.0, Win32 API, and XML
Databases: Microsoft Access.
Server: Win NT 4.0, Microsoft Internet Information Server 4.0
Hardware/Software Requirement for the client
The LTGIS tool has two major components,
II. The Viewer
I. The Data Converter
The data converter component resides on the server and is responsible for converting the data from a standard DXF file to the LTGIS data format, which is readable by the Viewer, deployed onto the client machine.
II. The Viewer
The Viewer is an ActiveX control, which displays the drawing files (vector maps) with basic entity like line, arcs, point and text. The viewer is capable of rendering the vector data directly, which is downloaded from the server when the user accesses the map for the first time. Thereafter, there is no transaction between the server and the client for any of the vector map data unless user requests for a different map or retrieves attribute data.
The Viewer accepts the data from the Server in the form of XML strings. Hence the Viewer can display any data format. Once the Viewer receives the data there is no interaction with the server as far as the basic GIS functionality is concerned. The map navigation and other GIS functionalities are performed at the client end. Hence the process reduces the network traffic and increases the overall performance of the application.
Figure 2: The Viewer
The functionalities supported by the Viewer (Fig. 2) are listed below
The Map Display Area
This is the area where the map data gets rendered. The Map Display area has eight triangle-shaped buttons these buttons provide direct panning of the map in the eight cardinal directions.
This functionality shows an overview of the entire map. The extents of the "Map Display Area" are indicated by a rectangular outline in the Aerial View. At each instance of map Zoom In, Zoom Out or Pan in the Map Display Area, the rectangle is changed to show the current state in "Aerial view". The Aerial View also supports Pan functionality by holding and moving the rectangle in the Aerial view window.
The viewer provides basic Map Navigation functionalities like -
This functionality provides for selecting individual entities on the map and displaying the relevant attributes attached to it.
Map Name Display area
This functionality displays the name/title of the map being selected. This is an added functionality, which would be useful if the user is working on various categories and numbers of map
This functionalities searches for the graphic entities, which the user wants to locate, for which the tool exposes some APIs through which the user can pass on the information about the entity to search. (This functionality is not seen in Fig. No: 2)
During user testing one major finding was that additional functionalities are required to enhance the quality of the Viewer. Some key functionalities as mentioned below, could be included in system to make it robust, user friendly and satisfy the basic needs of the GIS users.
The tool is very useful for corporate world as well as for industries that are wide spread in term of geographical areas and business, where tracking of human resources & business-related assets is very critical, time consuming and laborious. The "LTGIS" tool is a cost-effective solution, where such industries can overcome their problem in locating resources, facilities, and their whereabouts and associated attribute data, maintaining consistent database of their resources through out the organization, at the fingertip by just a single click. The following case study illustrates an effective implementation.
Case Study - Employee and Facility Information System (EmFIS)
Knowing "what is where" is a question of fundamental interest, and corporate set-ups are no exception. The answers provide for optimum utilization and efficient management of all resources. The Employee and Facility Information System (EmFIS) is a tool that addresses and facilitates the management of human resources. It handles queries and provides solutions involving spatial relationships, through a decision-making process. The software offers a pleasing and user-friendly interface and depicts solutions in a graphical form.
EmFIS is for the management of human resources and facilities, which in many organizations are geographically distributed over several buildings and at different locations. Therefore the need for a GIS application was identified to process spatial queries and provides solutions involving spatial relationships. This would in turn aid optimum utilization and efficient management of all resources in term of occupancy and space. Further it ensures consistency by maintaining a single database throughout the organization. It helps in allocation & deallocation of human resources, identifying latest employee location, finding vacant areas for suitable usage and facility available.
Traditionally, maintaining employee records is a laborious procedure and is usually centered around the HR department. Acquiring information related to employees can be facilitated by developing a Web based GIS solution. This application will help in locating employees, along with HR details, telephone extension, facilities allocated etc.
ActiveX Control: MS Visual Basic 6.0
Tool: LTGIS Tool
The Functionalities provided by the EmFIS
In cases where the requirements of a GIS application are limited to basic functionalities, it may not be possible to bear the burden of expensive GIS software. The LTGIS tool provides a cost-effective alternative. Also the design of the tool makes it a viable solution for the Intranet/Internet deployment, as there are very few interactions between the server and the client hence tackling the problem of heavy network traffic.
The authors wish to acknowledge the contribution of the Mr. S.V. Bhosale, GIS Team at LTITL and Mr. P. Ramakrishna (formerly of LTITL) in the development of this Viewer.