[Proj] WGS84 to NAD27 Coordinate conversion in Android

[Robb Main]

I need to convert WGS84 (lat, long) coordinates from GPS to NAD27 UTM
Eastings & Northings coordinates, primarily in Canada, in an Android
environment. To maximize accuracy of the end result, I believe the NTv2
grid corrections must be applied (though adding 13.5MB to the final
solution is not desireable).

I've looked at Proj.4 codebase, and I'm not at all sure it's the best tool
for this purpose. The JNI support for proj.4 appears to be for java support
under linux/windows/macos. GDAL uses proj.4 & appears to build for android
( https://trac.osgeo.org/gdal/wiki/BuildingForAndroid ), so it _IS_
possible (with some pain), though I'm not sure this is current info.
Regardless, GDAL is overkill for my needs, as all I need is coordinates.

I also found the proj4j library (a java port of the proj4 code -
http://svn.osgeo.org/metacrs/proj4j/trunk/src/README.html), though it looks
like it was last updated 5 years ago, and its not clear if grid support was
ever fully implemented / operational.

I found CTS ( https://github.com/orbisgis/cts ), which is a straight JAVA
library, implementing the required tranformations & supporting grids, but
there is little information / no examples on its use. Since it is pure
java, I expect it would be easier to implement in an android build
environment.

Please comment on the above if you have experience with them, or point me
in the right direction if you have some other suggestion.

Thank you.
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