geom_segment with fixed characteristics?

[Ben Bolker]

(Having answered a few questions here, I feel entitled to ask my own
boneheaded question now ...)

Dear ggplot'ers,

I'm trying to annotate a plot.
From the code below, I expected to see a red line running diagonally
partway across the plot.
What am I missing ... ?
(geom_abline is added here just as a separate trial, to ensure that
I really can add layers)

library(ggplot2)
t1 <- ggplot(data.frame(x=runif(10,max=30),y=runif(10,max=0.05)),
aes(x=x,y=y))+xlim(0,30)+ylim(0,0.05)+geom_point()
t1+geom_segment(data=NULL,x=1,x.end=20,y=0.01,y.end=0.04,linetype=2,colour="red")+
geom_abline(intercept=0,slope=0.01,colour="blue")

cheers
Ben Bolker

[Brandon Hurr]

I'm not sure if this is the answer you're looking for since the line isn't going across the middle of the plot like you suggested but putting the x,xend,y, yend in aes() it seems to work...

library(ggplot2)

t1 <- ggplot(data.frame(x=runif(10,max=30),y=runif(10,max=0.05)),

            aes(x=x,y=y))+xlim(0,30)+ylim(0,0.05)+geom_point()

t1+geom_segment(data=NULL,aes(x=1,xend=20,y=0.01,yend=0.04),linetype=2,colour="red")+

geom_abline(intercept=0,slope=0.01,colour="blue")

On Tue, Nov 9, 2010 at 16:48, Ben Bolker <bbo...@gmail.com> wrote:

geom_segment(data=NULL,x=1,x.end=20,y=0.01,y.end=0.04,linetype=2,colour="red")

When I tried the geom_segment call on its own it didn't like x.end or y.end, it seemed to want xend and yend. 

Brandon 

[Luciano Selzer]

Dear Ben, you forgot to make the aes call in geom segment and it's xend and yend. No point in the middle.

Here's the right code

library(ggplot2)

t1 <- ggplot(data.frame(x=runif(10,max=30),y=runif(10,max=0.05)),

            aes(x=x,y=y))+xlim(0,30)+ylim(0,0.05)+geom_point()

t1+geom_segment(data=NULL, aes(x=1,xend=20,y=0.01,yend=0.04),linetype=2,colour="red")+

geom_abline(intercept=0,slope=0.01,colour="blue")

HTH

Luciano

2010/11/9 Ben Bolker <bbo...@gmail.com>

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[Fernando Gonzalez]

Hi Ben,

'aes' within geom_segment and avoid the dots in 'x.end' and 'y.end'?

library(ggplot2)

t1 <- ggplot(data.frame(x=runif(10,max=30),y=runif(10,max=0.05)),

            aes(x=x,y=y))+xlim(0,30)+ylim(0,0.05)+geom_point()

t1+geom_segment(data=NULL,aes(x=1,xend=20,y=0.01,yend=0.04),linetype=2,colour="red")+

geom_abline(intercept=0,slope=0.01,colour="blue")

2010/11/9 Ben Bolker <bbo...@gmail.com>

[Hadley Wickham]

> Dear Ben, you forgot to make the aes call in geom segment and it's xend and
> yend. No point in the middle.

You shouldn't have to put the values in the aesthetics, but I think
there's a bug in that case where there is no data and all aesthetics
are set, not mapped.

Hadley

--
Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/

[Ben Bolker]

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On 11/09/2010 02:37 PM, Hadley Wickham wrote:
>> Dear Ben, you forgot to make the aes call in geom segment and it's xend and
>> yend. No point in the middle.
>
> You shouldn't have to put the values in the aesthetics, but I think
> there's a bug in that case where there is no data and all aesthetics
> are set, not mapped.
>
> Hadley
>
>

Good to know I was only being a little bit boneheaded. Thanks for the
help everyone.
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