Abstract With the declaration of India’s new
map policy (NMP), user community is looking
towards its impact on spatial accuracy of GIS
theme maps arising out of transformation from
existing system (Polyconic Projection on Everest
1830 spheroid datum) to Open series maps (OSM in
UTM projection on WGS 84 ellipsoid) and vice versa.
This results in registration error of existing maps with
new maps. This study aims at finding out the impact
of transformation on the spatial location and to
determine the extent to which the existing theme
layers can be used along with the new series maps
without losing accuracy. Results show that there are
some geographic regions in India whose GIS
database can be used as it is available, depending
on the scale and within the acceptable positional
accuracy. For other region, depending on the scale
of theme layers, a detail analysis of the situation will
be required depending on project requirements.