choosIng An APPRoPRIAte PRojectIon
Although an unlimited number of arrangements of the earth’s graticule is possible,
only comparatively few are in common use. The cartographer should be aware of the
advantages and limits of at least the most widely used of these.
Although map projections are now created by computer rather than by manual
means, this does not relieve the mapmaker of the task of choosing an appropriate
1
Another way of creating an interrupted projection is by joining a series of azimuthal projection seg-
ments, as in the star-shaped projection.
The earth’s graticule and Projections 123
projection from those available. Even if the computer program provides a list of suit-
able projections for a given task, the cartographer must be able to make an intelligent
choice among them. While two or more projections may be suitable, probably not all
will illustrate or communicate the given situation equally well. A well-chosen projec-
tion can enhance the communicative value of the map; a poorly chosen projection
may even mislead the map reader.
To make the best choice, it is necessary to consider the purpose of the map, the
subject of the map, the size and shape of the subject area, the location of the subject
area, the audience, and the size and shape of the page. Other considerations are the
appearance of the graticule, the general attractiveness of the projection, and the avail-
ability of the projection within the chosen software program.
fIgURe 6.36.
Goode’s homolosine projection is a combination of the sinusoidal and Moll-
weide (homolographic) projections. It is almost always in interrupted form.
fIgURe 6.37.
An interrupted projection can be condensed to gain scale.
124 THe geOgRaPHiC anD CaRTOgRaPHiC FRaMeWORK
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