Projection Specifications¶
GMT offers 31 map projections. These are specified using the -J common option. There are two conventions you may use: (a) GMT-style syntax and (b) Proj4-style syntax. The projection codes for the GMT-style and the Proj4-style are tabulated below.
| GMT PROJECTION CODES | Proj4 PROJECTION CODES | |
|---|---|---|
| -J (upper case for width, lower case for scale) | -J (lower case for scale only) | |
| -JAlon0/lat0[/horizon]/width | -Jlaea/lon0/lat0[/horizon]/scale | Lambert azimuthal equal area … |
| -JBlon0/lat0/lat1/lat2/width | -Jaea/lon0/lat0/lat1/lat2/scale | Albers conic equal area … |
| -JClon0/lat0/width | -Jcass/lon0/lat0/scale | Cassini cylindrical … |
| -JCyl_stere/[lon0[/lat0/]]width | -Jcyl_stere/[lon0[/lat0]/]scale | Cylindrical stereographic … |
| -JDlon0/lat0/lat1/lat2/width | -Jeqdc/lon0/lat0/lat1/lat2/scale | Equidistant conic … |
| -JElon0/lat0[/horizon]/width | -Jaeqd/lon0/lat0[/horizon]/scale | Azimuthal equidistant … |
| -JFlon0/lat0[/horizon]/width | -Jgnom/lon0/lat0[/horizon]/scale | Azimuthal gnomonic … |
| -JGlon0/lat0[/horizon]/width | -Jortho/lon0/lat0[/horizon]/scale | Azimuthal orthographic … |
| -JGlon0/lat0/alt/azim/tilt/twist/W/H/width | -Jnsper/lon0/lat0/alt/azim/tilt/twist/W/H/scale | General perspective … |
| -JH[lon0/]width | -Jhammer/lon0/scale | Hammer equal area … |
| -JI[lon0/]width | -Jsinu/lat0/scale | Sinusoidal equal area … |
| -JJ[lon0/]width | -Jmill/lon0/scale | Miller cylindrical … |
| -JKf[lon0/]width | -Jeck4/lon0/scale | Eckert IV equal area … |
| -JKs[lon0/]width | -Jeck6/lon0/scale | Eckert VI equal area … |
| -JLlon0/lat0/lat1/lat2/width | -Jlcc/lon0/lat0/lat1/lat2/scale | Lambert conic conformal … |
| -JM[lon0[/lat0]/]width | -Jmerc/[lon0[/lat0/]]scale | Mercator cylindrical … |
| -JN[lon0/]width | -Jrobin/[lon0/]scale | Robinson … |
| -JOalon0/lat0/azim/width | -Jomerc/lon0/lat0/azim/scale | Oblique Mercator, 1: origin and azim … |
| -JOblon0/lat0/lon1/lat1/width | -Jomerc/lon0/lat0/lon1/lat1/scale | Oblique Mercator, 2: two points … |
| -JOclon0/lat0/lonp/latp/width | -Jomercp/lon0/lat0/lonp/latp/scale | Oblique Mercator, 3: origin and pole … |
| -JP[a]width[/origin][r|z] | -Jpolar/[a]scale[/origin][r|z] | Polar [azimuthal] (\(\theta, r\)) (or cylindrical) |
| -JPoly[lon0[/lat0]/]width | -Jpoly/[lon0[/lat0/]]scale | (American) polyconic … |
| -JQ[lon0[/lat0/]]width | -Jeqc/[lon0[/lat0/]]scale | Equidistant cylindrical … |
| -JR[lon0/]width | -Jwintri/[lon0/]scale | Winkel Tripel … |
| -JSlon0/lat0[/horizon]/width | -Jstere/lon0/lat0[/horizon]/scale | General stereographic … |
| -JT[lon0[/lat0]/]width | -Jtmerc/[lon0[/lat0/]]scale | Transverse Mercator … |
| -JUzone/width | -Jutm/zone/scale | Universal Transverse Mercator (UTM) … |
| -JV[lon0/]width | -Jvandg/[lon0/]scale | Van der Grinten … |
| -JW[lon0/]width | -Jmoll/[lon0/]scale | Mollweide … |
| -JXwidth[l|pexp|T|t][/height[l|pexp|T|t]][d] | -Jxyxscale[l|pexp|T|t][/yscale[l|pexp|T|t]][d] | Linear, log\(_{10}\), \(x^a-y^b\), and time … |
| -JYlon0/lat0/width | -Jcea/lon0/lat0/scale | Cylindrical equal area … |