Oblique Mercator Projection

Wg Cdr Rajagopal

Oblique Mercator

Index

Introduction to Oblique Mercator

  • Oblique Mercator is useful for flying specified great circle routes
  • A datum great circle called false equator is taken as the parallel of tangency
  • Scale is within 1% error up to 480 NM on either side of the Datum Great Circle
  • Scale expansion is constantly equal to the secant of distance from datum great circle
  • The projection is orthomorphic since the scale expansion same in all directions and Meridians and parallels cut at right angles

Properties of Oblique Mercator

  • Meridians and parallels are complex curves intersect at right angles
  • Chart convergence is same at earth convergence only at the Poles, Equator and Datum great circle
  • Great circles as well as rhumb lines are complex curves except the great circle of tangency which is a straight line

Best of luck