Web GIS using Open Source

 Background:

 

GIS has become an indispensable tool for managing, analyzing and decision making by seamlessly combining both spatial and non-spatial data. Advent of web technologies and advancement in networks has made it possible to integrate these stand-alone systems so that data in one system can be related to the other. This has also enabled E-Governance by the Government bodies for conducting its functions in a citizen-centric manner. WWW is the E-Governance enabling technology because it enables transparency in the data and makes information readily available to the citizens. Web enabled GIS applications become the trend-setters for promoting G-Governance.

 Further, the growth of Open Source software in the GIS arena has been exemplary. The availability of the source code and the right to modify enables unlimited tuning and improvement of software.

 So, GIS Division, NIC, Bhubaneswar has made an attempt to prepare following 3  dynamic models built on Open Source GIS-Server interacting with GIS data and external data source ( Census-2001) through scripting.

  1. Browse Map: Flexibility in user-selectable layers on/off.
  2. Query Map: Retrieval of spatial data based on query built with non-spatial attributes.
  3. Thematic Map: Classification of spatial data as thematic maps based on user selectable parameter,

 

Operational Methods of the Modules:

 

MODULE 1:

 

Browse Map.  A user interface where the users would be able to browse the map  layer/layers . From the main menu, the user has to select the “ Browse Map” .  The sub-menu will appear with various layers. Here, the user will get 3 options: 1. Browse Layer, 2. Identify and 3. Map mode. One can activate/display the layers in the Browse Map mode only.

To Browse a layer, one has to activate the Browse Map mode, then select the layers from the table followed by “Refresh Map” option so that the selected layer will display on the Map frame. To select more than one layer, Press the “ Ctrl” button and  select the layers. After each selection, User has to refresh the map by clicking on “Refresh Map” option.

To see the attribute information of a browsed layer, one has to activate “Identify” mode and on mouse click on the map, attribute information related to that layer will display. To browse the another layer, the user again has to go Browse Layer mode. In Map Mode, simple map will display on the screen. The User can also zooming in/out and panning the maps .

 

MODULE 2:

 

Query Map.  From the main menu, an user can directly go to the Query Based Map generation table by selecting Query Map option. One can generate village wise maps applying conditions. User has to select the parameters as per her/his interest from the Menu and has to provide the conditions and values. Map title can be provided by the user. Then click on Draw map option followed by View Map option. The Map will display satisfying the query. One can list out the selected village names by selecting “ Generate Table” option from the Menu.

 

For Example: If one has to know the villages, where there is no Educational facilities. For that, User has to select the field “Education Facility” from the field menu and then apply the condition, i.e “Equal” and then provide the Value ( either 0,1 or 2).

 

 

 

 

 

 

 

 

 

(Y/N) = YES/NO (A/NA) = AVAILABLE/NOT AVAILALBLE

Codes used for --(Y/N) or (A/NA) are--

 

 

 

VALUE IS : 1- FOR YES OR AVAILABLE,  AND

 

 

 

                  2- FOR NO OR NOT AVAILABLE

 

 

 

                  0- For Nil information/Not available

Codes used for giving distance by ranges where amenites are not available are--

 

 

 

RANGE CODE 1 FOR < 5 Kms

 

 

 

RANGE CODE 2 FOR  5 TO 10 Kms

 

 

 

RANGE CODE 3 FOR > 10 Kms

 

 MODULE 3:

 

Thematic Map. A flexible user interface where the users would select the theme or parameter to generate  a dynamic thematic/choropleth map at Block Level.