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## 6.4.1 Hammer projection (-Jh -JH)

The equal-area Hammer projection, first presented by the German mathematician Ernst von Hammer in 1892, is also known as Hammer-Aitoff (the Aitoff projection looks similar, but is not equal-area). The border is an ellipse, equator and central meridian are straight lines, while other parallels and meridians are complex curves. The projection is defined by selecting:

- The central meridian [Middle of your map].
- Scale along equator in inch/degree or 1:xxxxx (-Jh), or map width (-JH).

A view of the Pacific ocean using the Dateline as central meridian is accomplished thus

    pscoast -Rg -JH4.5i -Bg30/g15 -Dc -A10000 -Gblack -P > GMT_hammer.ps

Figure 6.25: World map using the Hammer projection.

Next: 6.4.2 Mollweide projection (-Jw Up: 6.4 Miscellaneous projections Previous: 6.4 Miscellaneous projections Contents Index