Projected Coordinate System Nepal

Nepal uses Everest 1830 ellipsoid which is projected to UTM (cylindrical projection). While projecting the ellipsoid to UTM, Nepal’s system uses three different false datum for longitude - 81°, 84° and 87°. The X coordinate for each of  these longitudes is 500000 meters. To explain it further, the x-coordinate at 81° is 500000 meters. The x-coordinate keeps on increasing till 82° 30’. The longitude between 82° 30’ and 85° 30’ is the area of 84°, where 84°, similar to 81°, again corresponds to 500000 m. 82° 30’ is less than 500000 m and 85° 30’ is more than 500000m. Same is the case for 87°. We use the scale factor of 0.9999.  

The google earth uses WGS 1984 or WGS-84 coordinate system. 81°, 84°, 87° etc are not the same as that appears on google earth. The difference between Everest 1830 ellipsoid and WGS-84 ellipsoid near Nepal  is around 2.5 seconds if not more. 

Downloadable zip file