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6.3.6 Cylindrical equidistant projection (-Jq -JQ)

This simple cylindrical projection is really a linear scaling of longitudes and latitudes. The most common form is the Plate Carrée projection, where the scaling of longitudes and latitudes is the same. All meridians and parallels are straight lines. The projection can be defined by:

The first two of these are optional and have defaults. When the standard parallel is defined, the central meridian must be supplied as well.

A world map centered on the dateline using this projection can be obtained by running the command:




pscoast -Rg -JQ4.5i -B60f30g30 -Dc -A5000 -Gblack -P > GMT_equi_cyl.ps


Figure 6.20: World map using the Plate Carrée projection.
\includegraphics{scripts/GMT_equi_cyl}

Different relative scalings of longitudes and latitudes can be obtained by selecting a standard parallel different from the equator. Some selections for standard parallels have practical properties as shown in Table 6.1.

Table 6.1: Standard parallels for some cylindrical equidistant projections.
Projection Standard parallel
Grafarend and Niermann, minimum linear distortion 61.7°
Ronald Miller Equirectangular 50.5°
Ronald Miller, minimum continental distortion 43.5°
Grafarend and Niermann 42°
Ronald Miller, minimum overall distortion 37.5°
Plate Carrée, Simple Cylindrical, Plain/Plane



next up previous contents index
Next: 6.3.7 Cylindrical equal-area projections Up: 6.3 Cylindrical projections Previous: 6.3.5 Cassini cylindrical projection   Contents   Index
Paul Wessel 2008-05-15