Abstract
Realisation of National Spatial Data Infrastructure (NSDI) is the current national focus. NSDI is proposed as a single window mechanism for providing access to the spatial data being generated and managed by various agencies in the country. It is visualised as a network of databases consisting of the domain specific databases created and managed by various agencies like Survey of India, Geological Survey of India etc. and a central database having metadata to be managed by NSDI secretariat. Towards this, a national task force has been set up by Department of Science and Technology which is looking at all the related issues including evolution of spatial database standards at various domain servers as well as the metadata standards for providing single window access to the domain databases.

Evolution of mechanisms for exchange of spatial data sets is an integral part of such a system. Towards this, efforts have been made to define the National Spatial Data Exchange (NSDE) formats. These will have to be supplemented with automated procedures for inter-conversion of data from domain to NSDE format and vice-versa.

This paper describes the GIS based automated procedures for two-way data exchange between National (Natural) Resources Information System (NRIS) to proposed NSDE format along with the results obtained by applying these conversion processes for a study area. These have been presented to a sub-group on NSDI standards working under the guidance of NSDI task force and can be considered as guideline for development of such converters between various domain server databases and the NSDE.

The NRIS database design standards consists of various aspects including:

• The node database contents along with the naming conventions, associated coding schemes and the structure of data base organisation.
• The spatial database design standards including the spatial framework and the spatial and thematic accuracy levels enforced at the time of data input.

The proposed NSDE format is a set of ASCII files, independent of platform or GIS software, which is structured to incorporate various types of data elements like vector data on topography as well as various types of thematic data along with associated attributes data, Image data, DEM data, Coded raster GIS data etc.

Introduction
Geo-Spatial data, along with associated attribute data form the basis of information system useful for natural resources management, development of natural resources, planning of amenities and infrastructure, carrying out disaster management activities and management of environmental crises. Geo-Spatial information is being generated by various agencies like Survey of India (SOI), Geological Survey of India (GSI), National Atlas and Thematic Mapping Organisation (NATMO), Forest Survey of India (FSI), Department Of Space (DOS), National Bureau of Soil Surveys (NBSS), National Informatics Center (NIC) etc. Geographical Information Systems (GIS) is a modern computer based tool for management, analysis and presentation of Geo-Spatial data and extracting information needed for planning and decision making in various disciplines. These data are managed in different formats depending upon the GIS package used and at present there is no national level standard format for representing digital Geo-Spatial and associated attribute data so that exchange of data from one organisation to the other can take place easily and smoothly. Due to non-availability of standard format for Geo-Spatial data exchange, lot of effort requires to be put in converting the data in desired native format of the GIS package being used and this increases additional overheads in database creation in terms of time and manpower.

In order to overcome the above mentioned difficulties, National Spatial Data Infrastructure (NSDI) is proposed as a single window mechanism for providing platform independent and GIS package independent access to spatial data being generated and managed by various agencies. NSDI is visualised as a network of databases consisting of domain specific databases created and managed by various agencies like SOI, GSI etc. and a central database having metadata to be managed by NSDI secretariat. Towards this, a National Task Force is set up by Department of Science and Technology which is looking at all the related issues like evolution of spatial database standards at various domain servers as well as the metadata standards for providing single window access to the domain databases.

Evolution of mechanisms for exchange of spatial data sets is an integral part of such a system. Towards this, efforts are made to evolve the National Spatial Data Exchange (NSDE) format. These will have to be supplemented with automated procedures for inter-conversion of data from domain to NSDE format and vice-versa.

This paper describes the GIS based automated procedures for two-way data exchange between National (Natural) Resources Information System (NRIS) to proposed NSDE format along with the results obtained by applying these conversion processes for a study area. These have been presented to a sub-group on NSDI Standards working under the guidance of NSDI Task Force and can be considered as a guideline for development of such converters between various domain server databases and the NSDE. In the beginning, NRIS database standards and proposed NSDE format are briefly described.

NRIS Database Standards
The NRIS seeks to provide an integrated database for the use of remotely sensed data and collateral information in the framework of a spatial information system for management of natural resources and amenities planning at district, state, project and regional levels.

The NRIS database design standards consists of various aspects including node database contents along with naming conventions associated coding scheme and structure of the database organisation.

The spatial database design standard including the spatial framework and the spatial and thematic accuracy levels enforced at the time of data input.