[R] abline does not show on plot if slope differs from 0

2009-08-30 Thread Gábor Pozsgai
Hi,

Does anybody have a hint why this does not work?

plot(c(1991,2000), c(-1,10))abline(a=6, b=-1, col=dark grey, lty=dashed)

It does not generate an error message, but the line does not turn up.

If b=0 it works fine. If I change the axes of the plot to
plot(c(1,10), c(-1,10)) it does work fine as well.

Thanks,
Gabor

-- 
Pozsgai Gábor
www.coleoptera.hu
www.photogabor.com

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Re: [R] abline does not show on plot if slope differs from 0

2009-08-30 Thread jim holtman
Very simple, look at the x-axis you are plotting with.   If you want
the line, then use:

abline(a=1996, b=-1, col=dark grey, lty=dashed)


On Sun, Aug 30, 2009 at 12:25 PM, Gábor Pozsgaipozsg...@gmail.com wrote:
 Hi,

 Does anybody have a hint why this does not work?

 plot(c(1991,2000), c(-1,10))abline(a=6, b=-1, col=dark grey, lty=dashed)

 It does not generate an error message, but the line does not turn up.

 If b=0 it works fine. If I change the axes of the plot to
 plot(c(1,10), c(-1,10)) it does work fine as well.

 Thanks,
 Gabor

 --
 Pozsgai Gábor
 www.coleoptera.hu
 www.photogabor.com

 __
 R-help@r-project.org mailing list
 https://stat.ethz.ch/mailman/listinfo/r-help
 PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
 and provide commented, minimal, self-contained, reproducible code.




-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?

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Re: [R] abline does not show on plot if slope differs from 0

2009-08-30 Thread Gabor Grothendieck
The intercept, a, is the value when x = 0.   Thus if you want y = 6
when x = 1991 then the line is y = 6 - (x-1991) = 1997 - x so a = 1997:

abline(a=1997, b=-1, col=dark grey, lty=dashed)


On Sun, Aug 30, 2009 at 12:25 PM, Gábor Pozsgaipozsg...@gmail.com wrote:
 Hi,

 Does anybody have a hint why this does not work?

 plot(c(1991,2000), c(-1,10))abline(a=6, b=-1, col=dark grey, lty=dashed)

 It does not generate an error message, but the line does not turn up.

 If b=0 it works fine. If I change the axes of the plot to
 plot(c(1,10), c(-1,10)) it does work fine as well.

 Thanks,
 Gabor

 --
 Pozsgai Gábor
 www.coleoptera.hu
 www.photogabor.com

 __
 R-help@r-project.org mailing list
 https://stat.ethz.ch/mailman/listinfo/r-help
 PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
 and provide commented, minimal, self-contained, reproducible code.


__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.