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Non-linear scales in Polar plot

Posted: Thu Sep 29, 2005 2:03 pm
by miv
Dear Admin,

it has been a while since I asked for a possibility to draw logarithmic scale in polar mode. Just checked one and a half year after, and it appears it is still not there... Is there any plans to add this? Because particularly I need to display values in dB, which can easily be a negative value, probably this can not be achieved directly, but rather by mapping the tick labels placeholders to some table that has the values needed to be displayed. This is needed to display antenna radiation patterns which almost in 100% cases are drawn in logarithmic and have negative scale values in dB, say from -40...+10 dB.

Thanks.

Posted: Thu Sep 29, 2005 3:11 pm
by DPlotAdmin
Sorry, I don't recall a request for log scales on polar plots. But I'll add this to the to-do list.

You can plot negative values on a polar chart for the last several versions, though. So you could use Edit>Operate on Y with Y=log10(Y) to plot the logarithms of the amplitudes. The only trouble with this is the axis labels will be the logarithms rather than the actual amplitudes. But it sounds like this might be what you want anyway?

Posted: Thu Sep 29, 2005 10:36 pm
by miv
Can DPlotJr do this through DPlotLib? This is what I use, from within a VB app.

Thks.

Posted: Thu Sep 29, 2005 11:23 pm
by DPlotAdmin
No. You'd need to do the transformation in your program before sending the data to DPlot Jr.