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O.3.4 Label placement at simple line intersections

Often, it will suffice to place contours at the imaginary intersections between the contour lines and a well-placed straight line segment. The -Gl or -GL algorithms work well in those cases: 




pscoast -R50/160/-15/15 -JM5.5i -Glightgray -A500 -K -P > GMT_App_O_4.ps
grdcontour geoid.grd -J -O -B20f10WSne -C10 -A20+d+s8 -GLZ-/Z+ -S10 -T:LH >> GMT_App_O_4.ps




The obvious choice in this example is to specify a great circle between the high and the low, thus placing all labels between these extrema.

Figure O.4: Labels are placed at the intersections between contours and the great circle specified in the -GL option.
\begin{figure}\centering\epsfig{figure=eps/GMT_App_O_4.eps}\end{figure}
The thin debug line in Figure O.4 shows the great circle and the intersections where labels are plotted. Note that any number of such lines could be specified; here we are content with just one.

next up previous contents index
Next: O.3.5 Label placement at Up: O.3 Examples of Contour Previous: O.3.3 Prescribed label placements   Contents   Index
Paul Wessel 2004-10-01