Coordinate Systems in Nepal

 Geographic Coordinate System (GCS)

Most of the spatial data and maps of Nepal are based on two System. 

1. Everest 1830 is mostly used in topographic maps and maps produced by governmental agencies like Department of Survey. 

2. WGS84 is used in most of the images and maps available over the internet are referenced in this system.

Projected Coordinate System (PCS)

For Projection,  the projection system used is Universal Transverse Mercator (UTM) which may be based on either WGS84 or Everest 1830.

Nepal lies in UTM zone between 44 and 45. The 44 zone covers western half of Nepal and 45 covers the eastern half. This projection is based on WGS84

Due to greater expansion in east-west direction of Nepal, Survey Department of Nepal uses Modified UTM (MUTM) for increasing accuracy in cadastral survey. Based on Everest 1830 the two zones are modified into three zones differentiated by longitude of the coordinate as 81, 84, and 87  covering west, central and eastern Nepal respectively.

 

Transformation between the two PCS

There is a slight difference between these UTM and MUTM system used in Nepal. We can do geographic transformation from one PCS to the other one by using following parameters:

Source GCS: Everest 1830 and Target GCS: WGS 1984

Method: Molodensky

Translation parameters:

Translation along X axis (in meters) = 293.17

Translation along Y axis (in meters) = 726.18

Translation along Z axis (in meters) = 245.36

Similarly, In order to do geographic transformation from WGS 1984 (Source GCS) to Everest 1830 (Target GCS) we use same method with same values with negative signs in front.

Download MUTM Coordinate system for GIS.

MUTM 84

MUTM 87

MUTM 81