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pscontour for direct contouring

Find sample data files and scripts in /GMT_data/budo01

makecpt -Ctopo -T970/1010/0.5 > budo.cpt

pscontour xyzm.prn -R975/1035/985/1045 -JX15 -Cbudo.cpt -L0.5/0/200/200p -W0.7p -P -B10g10  > budo1.ps
makecpt is to create a color palette file using ready-made color setting (topo) and
-Tzmin/zmax/increment.  Output file is budo.cpt.
pscontour sets up triangulation network and draw contourlines in the network directly.
-L defines stroke of triangles.  Color palette file is used to define the contours to be drawn.

If necessary, enlarge this and check each triangle fits to real topography.  

Triangulation error:  For example in the map below, assume (980, 1040, 1002), (990, 1030, 1002),
(980, 1030, 998), (990, 1040, 998).  In this case, there is no way to distinguish if there is
1002 m ridge between (980, 1040, 1002) and (990, 1030, 1002) or 998 m trough between
(980, 1030, 998) and (990, 1040, 998) unless the height of (985, 1035) is known.  Check and
change triangulation adding (985, 1035, 998) or in the field, measure any linear features in
smaller interval to avoid this problem.



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