The Graduate Aptitude Test in Engineering is an examination conducted in India that primarily tests the comprehensive understanding of various undergraduate subjects in engineering and science for admission into the Masters Program and Job in Public Sector Companies.

The eligibility conditions for MTech Geomatics  that candidates, in general, are expected to meet in order to be considered for admission are:

A UG degree in Engineering in relevant stream with minimum 60% marks.

As you are not from engineering background I don't think you are eligible for GATE Geomatics Engineering .For M.tech in Geomatics Engineering you must have an B.tech degree.