next up previous contents index
Next: 4.4.1 Mesh-plot Up: 4. SESSION FOUR Previous: 4.3.1 Exercises   Contents   Index


4.4 Perspective views

Our final undertaking in this tutorial is to examine three-dimensional perspective views. GMT is currently limited to vantage points at infinity; thus we are unable to do fly-by's through canyons etc. The GMT module that produces perspective views of gridded data files is grdview. It can make two kinds of plots:

  1. Mesh or wire-frame plot (with or without superimposed contours)

  2. Color-coded surface (with optional shading, contours, or draping).

Regardless of plot type, some arguments must be specified; these are

  1. relief_file; a gridded data set of the surface.

  2. -J for the desired map projection.

  3. -JZheight for the vertical scaling.

  4. -Eazimuth/elevation for vantage point.

In addition, some options may be required:


Table 4.5: The most useful options in grdview.
Option Purpose
-Ccptfile The cptfile is required for color -coded surfaces and for contoured mesh plots
-Gdrape_file Assign colors using drape_file instead of relief_file
-Iintens_file File with illumination intensities
-Qm Selects mesh plot
-Qs[m] Surface plot using polygons; append m to show mesh. This option allows for -W
-Qidpi[g] Image by scan-line conversion. Specify dpi; append g to force gray-shade image. -B is disabled.
-Wpen Draw contours on top of surface (except with -Qi)




Subsections
next up previous contents index
Next: 4.4.1 Mesh-plot Up: 4. SESSION FOUR Previous: 4.3.1 Exercises   Contents   Index
Paul Wessel 2006-05-31