That is, the plane is normally placed above the north or south pole. Normally only one hemisphere, or a portion of it, is represented on Azimuthal projections. When projected from the center of the globe with the normal aspect, the typical grid appearance for Azimuthal projections shows parallels forming concentric circles, while meridians radiate out from the center. Click here for an example of the Projection of a Sphere onto a Plane with the Equatorial Aspect and Tangent Case. Tangency or Case Tangency or Case refers to the location or locations that a projection surface touches or cuts through the globe.
Distortion increases away from tangency.
It is important, therefore, when projecting the spherical surface onto a map projection, to locate tangency on or near the area of central focus or greatest interest. Additional graphic examples of the tangent case include the following versions of the Normal Cylindrical , Transverse Cylindrical , Oblique Cylindrical , Conic , and Azimuthal projections. Secant In secant case , the projection surface cuts through the globe to touch the surface at two lines as demonstrated also in Fig. Additional graphic examples of the secant case include the following versions of the Cylindrical , Conic , and Azimuthal projections. The aspect may sometimes be indicated in the name or description of a projection, e.g., Transverse Mercator , Oblique Orthographic , Space Oblique Mercator, etc.