Working with Polar Plots
Polar Coordinates
Consider a point in space:
This same point can also be located by its polar coordinates, [r,
Conversely, given a point [r,
Or use Mathcad's mapping functions to do these conversions for you.
Inserting a Polar Plot
You can use the 2D polar plot operator to plot points in terms of their polar coordinates.
To insert a polar plot into a Mathcad worksheet, choose Insert > Graph > Polar Plot, or choose the Polar Plot icon on the Graph toolbar.
You see the shell of a polar plot with the following placeholders.
You can plot a function:
or a set of data:
Data points are connected by a straight line by default. Use the plot formatting options, discussed below, to show symbols at each point or remove the lines connecting them. Just like X-Y plots, polar plots can have up to 16 traces.
Negative radii
A new feature in Mathcad 14 allows you to specify negative values for radii in polar plots, similar to the negative values allowed for the X and Y axes in X-Y plots. This is particularly useful when plotting in dB (log scale), which commonly occurs in the communications and antenna design industries.
Example
Previously, Mathcad phase translated the negative radii and gave them a positive radius value:
Show negative radii enabled on the radial axis produces the polar graph below.
Units
Mathcad uses radians for angles. Note the point in the plot below does not appear at 15° as you may have expected.
Without including units on the
Formatting polar plots
Double-click on a polar plot to format it.
On the Traces tab you can choose the number and color of the gridlines for both the radial and angular axes. You can display or suppress the numbers on each axis. The radial axis can be set to log scale or have markers applied. A marker appears as the purple dashed circle at the specified radius (0.3 below).
There are three axis style options: Perimeter, Crossed, or None.