UTM 46.5 for Myanmar..possible?

[knwin]

Since Myamar is covered by two UTM Zones, UTM46 and UTM47, it is some how not convenient in some applications when the study area (large) is across the zones. Especially when the whole country is needed to project for certain analysis/application,if either of UTM46 or UTM47 is used for the whole country, one part (almost half) will definitely be suffered from scale distortion that is beyond the maximum scale error of UTM zone's original design. Moreover most GPS will switch to actual zone on the ground when you cross one zone. Eg Mandalay is in UTM47 while Sagaing in UTM46.(Please check on Google Earth with UTM display). Calculating distance, direction and area extent from UTM coordinates is easy with pocket calculator. But if coordinates are from different zone computation is not straight forward.

What if we invent UTM46.5-meridian at 96 degree longitude (the rest parameters are same as 46 and 47 zones). Then the majority of the country (>90%) will be within one UTM ZONE.

Red lines indicate the boundary of UTM46.5 Zone (proposed)


Proposed UTM46.5N zone
Blue line is 96 deg longitude (Meridian)
Brown solid lines are at 93 and 99 degrees.
Brown dash lines are standar parallel lines (secant lines where the cylinder intersect WGS84 earth model) 180km apart from central meridian, where scale error is zero(true scale). Scale error increase away from these lines.


Orientation of map in different zone projection
Red line is 96 deg longitude line.

[knwin]

Update on Latest Myanmar UTM maps.

Most people think that as new maps are in UTM system, the maps are easy to use with GPS. In fact, these Myanmar UTM maps use different spheroid than WGS84 that is default to current GPS system. Myamar UTM maps use socalled "Myanmar Datum 2000". Actually it use the Everest 1830 spheroid which has different dimension from WGS 84. Everest 1830 dimensions are available online and in the GIS application. However the problem is the transformation parameters between WGS84 of GPS and Everest 1830 used in current map. To use GPS accurately on Myanmar UTM maps, at least three transformation parameters (DX, DY and DZ) are required to feed into GPS receiver. For more precise Geodetic applications scale and rotation information of the axes must be known in addition to these shifts. These parameter are not meant to release to the public yet. Without the transformation parameters your GPS locations will be shifted between 200 to 300 meter in specific direction.
Same spheroid may be used by more than one country (eg. Myanmar and Banglasdesh) but transformation parameters will be different as the spheroid is placed to fit with the specific country's averaged elevation.
Myanmar Datum 2000 = Spheroid + parameters specific to Myanmar