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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.
  –-JZ height for the vertical scaling.

4.
  -–E azimuth/elevation for vantage point.

In addition, some options may be required:

Table 4.5: The most useful options in grdview
Option | Purpose
-–C cptfile | The cptfile is required for color -coded surfaces and for contoured mesh plots
-–G drape_file | Assign colors using drape_file instead of relief_file
-–I intens_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
-–Qi dpi[ g] | Image by scan-line conversion. Specify dpi; append g to force gray-shade image. -–B is disabled.
-–W pen | Draw contours on top of surface (except with -–Qi)

- Mesh-plot
  - Exercises
- Color-coded view
  - Exercises

Next: Mesh-plot Up: SESSION FOUR Previous: Exercises