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The central cylindrical projection is a perspective cylindrical map projection. It corresponds to projecting the Earth's surface onto a cylinder tangent to the equator as if from a light source at Earth's center. The cylinder is then cut along one of the projected meridians and unrolled into a flat map. [1]
Examples are the sidewalk chalk drawings of Kurt Wenner and Julian Beever, [16] where the chalked image, the pavement, and the architectural surroundings all become part of an illusion. Art of this style can be produced by taking a photograph of an object or setting at a sharp oblique angle, then putting a grid over the photograph.
Artists may choose to "correct" perspective distortions, for example by drawing all spheres as perfect circles, or by drawing figures as if centered on the direction of view. In practice, unless the viewer observes the image from an extreme angle, like standing far to the side of a painting, the perspective normally looks more or less correct.
The foreshortening factor (1/2 in this example) is inversely proportional to the tangent of the angle (63.43° in this example) between the projection plane (colored brown) and the projection lines (dotted). Front view of the same. Oblique projection is a type of parallel projection: it projects an image by intersecting parallel rays (projectors)
Cylindrical perspective is a form of distortion caused by fisheye and panoramic lenses which reproduce straight horizontal lines above and below the lens axis level ...
The weak-perspective model thus approximates perspective projection while using a simpler model, similar to the pure (unscaled) orthographic perspective. It is a reasonable approximation when the depth of the object along the line of sight is small compared to the distance from the camera, and the field of view is small.
An example of a multiview orthographic drawing from a US Patent (1913), showing two views of the same object. Third angle projection is used. In third-angle projection , the object is conceptually located in quadrant III, i.e. it is positioned below and behind the viewing planes, the planes are transparent , and each view is pulled onto the ...
How the Earth is projected onto a cylinder. The projection: is cylindrical, that means it has a cylindrical projection surface [2] is normal, that means it has a normal aspect; is an equal-area projection, that means any two areas in the map have the same relative size compared to their size on the sphere.