```Date: Feb 3, 2013 2:51 AM
Author: Bob Hanlon
Subject: Re: Labelling each curve and changing grid in ParametricPlot

plot[tau_, omega_] := Module[{arg, abs},  {arg, abs} =   Factor[    Together[     ComplexExpand[      Through[{Arg, Abs}[(1 + I*2*omega)/         (1 + I*2*tau*omega)]]]]];  {arg/Degree, 20*Log10[abs]}]Show[ ParametricPlot[  Evaluate[   Table[    plot[tau, omega],    {omega, -0.5, -0.1, 0.05}]],  {tau, 7, 15},  PlotStyle ->   Directive[    Gray,    AbsoluteDashing[{5, 5}]]], ParametricPlot[  Evaluate[   Table[    plot[tau, omega],    {tau, Range[7, 15]}]],  {omega, -0.5, -0.01},  AspectRatio -> 1], Frame -> True, Axes -> False, PlotRange -> All, AspectRatio -> 1, Epilog -> {   Table[    Text[tau, plot[tau, -0.5], {2, 0}],    {tau, 8, 14, 2}],   Table[    Text[omega, plot[7, omega], {1.25, -1}],    {omega, -0.45, -0.15, 0.1}]}]Bob HanlonOn Sat, Feb 2, 2013 at 11:17 AM, Eduardo M. A. M. Mendes<emammendes@gmail.com> wrote:> Dear Bob>> Many thanks.  As usual I will have to spend time to understand your code.  I am too much of beginner.>> As for the grid, I was thinking of removing the standard grid all together and draw (just the dashed grid lines) lines for specific values of Omega.>> Regards>> Ed>>> On Feb 2, 2013, at 12:06 PM, Bob Hanlon <hanlonr357@gmail.com> wrote:>>> plot[tau_, omega_] :=>> Module[{arg, abs},>>  {arg, abs} =>>   Factor[>>    Together[>>     ComplexExpand[>>      Through[{Arg, Abs}[>>        (1 + I*2*omega)/(1 + I*2*tau*omega)]]]]];>>  {arg/Degree, 20*Log10[abs]}]>>>> ParametricPlot[>> Evaluate[>>  Table[>>   plot[tau, omega],>>   {tau, Range[7, 15]}]],>> {omega, -0.5, -0.01},>> AspectRatio -> 1,>> GridLines -> Automatic,>> GridLinesStyle -> Dashed,>> ImageSize -> Large,>> Epilog -> {>>   Table[>>    Text[tau, plot[tau, -0.5], {2, 0}],>>    {tau, 7, 15}]},>> Mesh -> 5]>>>>>> Bob Hanlon>>>>>> On Sat, Feb 2, 2013 at 1:18 AM, Eduardo M. A. M. Mendes>> <emammendes@gmail.com> wrote:>>> Hello>>>>>> I wonder whether someone out there could help me with the following problem.>>>>>> plot[\[Tau]_, \[CapitalOmega]_] := Module[{arg, abs},>>>   {arg, abs} = Factor[Together[ComplexExpand[>>>        Through[{Arg, Abs}[(1 + I*2*\[CapitalOmega])/(1 + I*2*\[Tau]*\[CapitalOmega])]]]]];>>>    {arg/Degree, 20*Log10[abs]}]>>>>>> ParametricPlot[Table[plot[\[Tau], \[CapitalOmega]], {\[Tau], {7, 8, 9, 10, 11, 12, 13, 14, 15}}],>>>  {\[CapitalOmega], -0.5, -0.01}, AspectRatio -> 1, GridLines -> Automatic,>>>  GridLinesStyle -> Dashed, ImageSize -> Large]>>>>>> I need to label each curve with the value of tau and, instead of the normal grid, a grid based on the values of Omega.>>>>>> I saw something related to the label problem on the net but could not figure out how to change it to my case.   Something with Epilog.>>>>>> Many thanks>>>>>> Ed>>>>>>>>>>
```