General HydroStatics
Ship Stability Software
Command of the Week
(New or interesting aspects of GHS that you may not know about)

(Requires GHS version 16.58B or later)

Polar plots are naturally a 360 degree experience, but sometimes only a single quadrant is of interest. Those times it'd be nice to see the real action as large as possible, rather than waste real estate on blank space 180 degrees away.

Fortunately, the ME PLOTSTART /POLAR command automatically does exactly that, drawing an expanded quadrant plot whenever all the plot angles fall within the same 90 degree range. For example:

me plotstart "Quadrant Plot" /polar
me plotlabel "Angle","Curve1","Curve2","Curve3","Curve4"
me 10,1,.333333,2.5,5
me 45,4,2.666666,5,2
me 80,9,9,7.5,-3
me plotend
report /preview

These commands produce this impressive Quadrant Plot:

But what if the full polar plot is wanted instead? That can be easily produced just by offsetting the final angle by 360 degrees so it no longer fits within the same 90 degree quadrant! So to turn this Quadrant Plot into a Full Polar Plot, just change the final ME data line as follows:

me 440,9,9,7.5,-3 `note 440=80+360 forces full polar plot

Since the angle hasn't really changed by adding 360 to it, the resulting curves will be identical... just displayed (much) smaller, so the default Quadrant Plot will usually be what you want instead of this:

Questions, comments, or requests?
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