Nonlinear Projections - Transformations and Projections in Computer Graphics - page 211

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standard parallel
standard parallel

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(a) (b)

Figure 4.61: Lambert Conic Conformal Projection.

Perspective conic . Neither conformal nor equal-area, this projection maintains true
scale at one standard latitude, while increasing distortion away from it. The principle
is illustrated in Figure 4.62a. A cone covers part of the globe and is tangent to one
latitude φ 0 .Givenapoint P on the globe (inside the cone), we extend the straight
segment from the center of the globe to P until it intersects the cone. The intersection
point is the projection P ∗ of P . A pole may be used instead of the center of the globe
as the center of projection.

r

φ 0

r 0

P *

P

φ

φ 0

(a) (b)

Figure 4.62: Conic Perspective Projection.