[R] ggplot2: annotated horizontal lines

[Dave Murray-Rust]

That's great - thanks!

On 4 Mar 2009, at 08:59, ONKELINX, Thierry wrote:

> Dear Dave,
>
> Another option would be to manually create the breaks of your plot.
>
> library(ggplot2)
> myBreaks <- sort(c(pretty(mtcars$mpg), min(mtcars$mpg)))
> ggplot(aes(x = wt, y = mpg), data = mtcars) + geom_point() +  
> geom_hline(yintercept = min(mtcars$mpg)) + scale_y_continuous(breaks  
> = myBreaks)
>
> HTH,
>
> Thierry
>
>
> ----------------------------------------------------------------------------
> ir. Thierry Onkelinx
> Instituut voor natuur- en bosonderzoek / Research Institute for  
> Nature and Forest
> Cel biometrie, methodologie en kwaliteitszorg / Section biometrics,  
> methodology and quality assurance
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> more than asking him to perform a post-mortem examination: he may be  
> able to say what the experiment died of.
> ~ Sir Ronald Aylmer Fisher
>
> The plural of anecdote is not data.
> ~ Roger Brinner
>
> The combination of some data and an aching desire for an answer does  
> not ensure that a reasonable answer can be extracted from a given  
> body of data.
> ~ John Tukey
>
> -----Oorspronkelijk bericht-----
> Van: r-help-bounces at r-project.org [mailto:r-help-bounces at r- 
> project.org] Namens baptiste auguie
> Verzonden: dinsdag 3 maart 2009 21:50
> Aan: Dave Murray-Rust
> CC: R Help
> Onderwerp: Re: [R] ggplot2: annotated horizontal lines
>
> I see your problem (although label should be outside the mapping in
> your case, i think).
>
> A possible workaround is to provide some dummy data, as the default
> NULL doesn't seem to work,
>
>  qplot( wt, mpg, data=mtcars ) +
>  geom_text(data=data.frame(x=0,y=0),mapping=aes(x=1,y=0),label="test")
>
> I'm sure Hadley will come up with a better explanation.
>
> Best,
>
> baptiste
>
> On 3 Mar 2009, at 19:51, Dave Murray-Rust wrote:
>
>>
>> On 3 Mar 2009, at 18:41, baptiste auguie wrote:
>>
>>> What's wrong with geom_text?
>>>
>>>> my.value = 0.65
>>>> qplot(1,1)+geom_hline(v=0)+
>>>>    geom_text(mapping=aes(x=1,y=0),label=paste(my.value),vjust=-1)
>>>
>>
>> Well, firstly I hadn't thought to use it. Ooops.
>>
>> Secondly, I can't make it just do a single value - it seems to want a
>> value for every point in the dataset, e.g.:
>>
>>> qplot( wt, mpg, data=mtcars ) +
>> geom_text(mapping=aes(x=1,y=0,label=paste("0.5"),vjust=-1))
>> Error in data.frame(..., check.names = FALSE) :
>>  arguments imply differing number of rows: 1, 32
>>
>> Cheers,
>> dave
>>
>>
>>>
>>> baptiste
>>>
>>> On 3 Mar 2009, at 18:10, Dave Murray-Rust wrote:
>>>
>>>> Hello,
>>>>
>>>> I'm using geom_hline to add a minimum line to my plot (representing
>>>> the best solution found so far by a search algorithm). I'd like to
>>>> annotate this line with it's numerical value to save trying to read
>>>> it
>>>> off the graph, but I can't see a clear way to do this - any ideas?
>>>>
>>>> (Alternatively, if this is against the spirit of the grammar of
>>>> graphics, is there a better way to represent the information?)
>>>>
>>>> Cheers,
>>>> dave
>>>>
>>>>
>>>> --
>>>> The University of Edinburgh is a charitable body, registered in
>>>> Scotland, with registration number SC005336.
>>>>
>>>> ______________________________________________
>>>> R-help at r-project.org mailing list
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>>>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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>>>
>>> _____________________________
>>>
>>> Baptiste Auguié
>>>
>>> School of Physics
>>> University of Exeter
>>> Stocker Road,
>>> Exeter, Devon,
>>> EX4 4QL, UK
>>>
>>> Phone: +44 1392 264187
>>>
>>> http://newton.ex.ac.uk/research/emag
>>> ______________________________
>>>
>>>
>>
>>
>> --
>> The University of Edinburgh is a charitable body, registered in
>> Scotland, with registration number SC005336.
>>
>
> _____________________________
>
> Baptiste Auguié
>
> School of Physics
> University of Exeter
> Stocker Road,
> Exeter, Devon,
> EX4 4QL, UK
>
> Phone: +44 1392 264187
>
> http://newton.ex.ac.uk/research/emag
>
> ______________________________________________
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-- 
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.