Perspective Cylindrical Projection

Wg Cdr Rajagopal

Cylindrical Projections

Index

Introduction to Cylindrical Projections

  • Cylindrical Projections are made by wrapping paper in Cylindrical Shape around the Reduced Earth
  • Paper touches reduced earth at the equator in a normal cylindrical projection
  • Equator is the parallel of tangency or origin since the paper touches the reduced earth at the Equator
  • Scale is correct only at equator since light travels correct length at equator

Scale of Cylindrical Projections

  • Scale of all perspective projections is correct at its parallel of tangency
  • Scale is correct at the equator since it is the parallel of tangency for a normal cylindrical projection
  • In a Normal Cylindrical Projection, the North-South scale expands proportionate to tangent of latitude
  • East-West scale expands proportionate to the secant of latitude in the cylindrical projection

Orthomorphism of Cylindrical Projections

  • Orthomorphism means bearings measured on chart same as that of earth
  • Perspective cylindrical projection is non-orthomorphic as scale expansion not equal on all directions
  • North-South scale varies as tangent of latitude while the East-West scale varies as secant of latitude

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