Jim and John,

Thanks for your replies. I ended up using both suggestions to plot the full
tide series and then overlay the averages for rise and fall in different
colours, which illustrated very well how such parameters can
be misleadings in some cases.

Regards,
Tony



2009/10/31 Jim Lemon <jim@bitwrit.com.au>

> On 10/31/2009 04:49 AM, Tony Greig wrote:
>
>> Hi,
>>
>> Two questions:
>>
>> 1 - Say I have average speed and directions for tide and I would like to
>> plot them on a polar plot, but with different colors so I can indicate the
>> two directions. I'm using polar.plot from the plotrix library. How can I
>> add
>> a second "b" and "dir.b" series to a polar.plot?
>>
>> library(plotrix)
>> a = 3
>> dir.a = 85
>> b = 4
>> dir.b = 250
>> polar.plot(a, dir.a, start = 90, clockwise = T, show.grid.labels = T,
>> radial.lim=c(0,5), line.col=2, lwd=2)
>>
>>
>> 2 - Which parameter in polar.plot can I use to set the orientation for the
>> grid labels which seem to default at 90 in my example above?
>>
>>
>>
> Hi Tony,
> The first one is easy:
>
> polar.plot(c(a,b), c(dir.a,dir.b), start = 90,
>  clockwise = T, show.grid.labels=FALSE,
>
>  radial.lim=c(0,5), line.col=2, lwd=2)
>
> I have had one other person as about an "add" option, and I might include
> that in a future version. The second one is a bit harder. You probably
> noticed that I changed the show.grid.labels argument to FALSE in the above.
>
> par(xpd=TRUE)
> boxed.labels(rep(0,5),1:5,1:5,border=NA)
> par(xpd=FALSE)
>
> This will put the labels vertically up from the center. Doing fancier
> things like having the labels at an angle would require calculating the
> positions, which isn't too hard.
>
> Jim
>
>

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