Geocart Projections

What is a projection?

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equidistant cylindric

equirectangular

Parameters: Standard parallel

Classifications

Geocart menu class: Cylindric
Cylindric
Equidistant

Graticule

Meridians: Equally spaced straight parallel lines more than half as long as the Equator.
Parallels: Equally spaced straight parallel lines, perpendicular to and having wider spacing than meridians
Poles: Straight lines equal in length to the Equator
Symmetry: About any meridian or the Equator

Scale

True along two standard parallels equidistant from the Equator and along all meridians
Too small along the Equator but increases with distance from the Equator along the parallels
Constant along any given parallel; same scale at the parallel of opposite sign

Distortion

Infinitesimally small circles on the globe (indicatrices) are circles on the map at latitudes 30° N. and S. for this choice of standard parallels. Elsewhere, area and local shape are distorted.

Other features

Simple modification of Plate Carree having east-west compression
Conceptually projected onto a cylinder secant to the globe along the chosen standard parallels
Not perspective

Usage

Simple outline maps of regions or of the world or for index maps Used only in the spherical form

Origin

Marinus of Tyre about A.D. 100

Other names

Equidistant Cylindrical
Rectangular
La Carte Parallelogrammatique 1 h
Die Rechteckige Plattkarte
Projection of Marinus
Gall Isographic (if standard parallels are latitudes 45° N. and S.)

Description adapted from J.P. Snyder and P.M. Voxland, An Album of Map Projections, U.S. Geological Survey Professional Paper 1453. United States Government Printing Office: 1989.