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Internet GIS applications on open source software


Raghunathan VS
State Informatics Officer, National Informatics Center, Kerala, India
[email protected]

Mahalaxmi Narayanan
Senior Systems Analyst, National Informatics Center
Tamil Nadu, India
[email protected]

The Dynamic Model of GIS built on Open Source tries to leverage on the use of freely available software from open source domain to query and draw maps based on the existing MIS running at different locations. This model talks to other data sources and allows queries and thematic mapping on required level of spatial data through simple browser interface. This ensures that the maps need not be distributed at different locations

For many years, we have been seeing isolated groups mastering GIS and working on separate pools of geo-datasets. One was not possibly aware of what the other was working on. However, with the boom of Internet GIS applications, today everybody can get to know what the others are doing and which data is available with whom. Also, the ultimate beneficiaries of Internet GIS would ultimately be the users or netizens who would explore GIS without the need for investing on GIS tools. For hosting GIS Services on the web, the infrastructure deployment in the form of Web Server, GIS Server, Database Server and other software could be expensive for many organizations. But the astounding growth of Open Source Software provides a much cheaper solution. The apprehension on how one could get solutions and support from open source community no longer exists. The availability of the source code and the right to modify enables the unlimited tuning and improvement of software. The right to redistribute and reuse these modifications and improvements to the code adds to all the advantages to be shared by large communities. A quick look at https://www.freegis.org will surely attract even a novice to take up GIS work.

At National Informatics Centre, we have initiated Open Source GIS Solutions for Internet based applications. One such application developed at Chennai is . In this website, the Animal Census population and large volume of Animal Disease Data are being shown as dynamic thematic maps. Also, user can customize the map (for the ranges, colours, legends and titles) and get the output map in the required format. Another application is where maps browsing, querying and drawing thematic maps dynamically have been enabled with Tamil Nadu districts map and Census – 2001 data.

The Dynamic Model of GIS built on Open Source tries to leverage on the use of freely available software from open source domain to query and draw maps based on the existing MIS running at different locations. This model talks to other data sources and allows queries and thematic mapping on required level of spatial data through simple browser interface. This ensures that the maps need not be distributed at different locations for obvious security reasons but still enable accessibility to citizens. Further, it reduces the effort involed in recreation/digitization of maps or other practical deployment difficulties. Also, Web Map Service (WMS) and Web Feature Service (WFS) enable “Distributed GIS” and “Distributed Geodatabase Management”.

Design Methodology
The design of the application has been split into different modules for easy development and better maintenance. Hence it can be hosted on any platform, be it Microsoft Windows or Linux or any other platform. The tools that have been used are available for all the platforms. However, our application was tested on Windows and Linux Platforms. The overall design is presented in Figure 1.

Modules
The application has a modular design and comprises of 7 modules. Eah module caters to an application functinality, namely

  • Making data Internet ready – Data acquisition. Associating non-spatial data for the spatial features.
  • Area or Region Selection – Selection of spatial entity for display
  • Simple Map Browsing – Selection of Map layers and Map window size
  • Spatial Query – Simple queries on the spatial features and the associated database
  • Non-Spatial Query – Database queries wherein the associated spatial figures are displayed as query results
  • Thematic/Choropleth Mapping – Thematic map generation based on user selection
  • Simple Map Browsing – Map browsing and querying