[R] Help with R

Rui Barradas ruipbarradas at sapo.pt
Sat Nov 19 21:33:49 CET 2016


First of all, there's a no homework policy in R-Help, but since it's the 
first time you post I'll try to give some help.

Now, you are trying to call two functions in one statement, system.file 
and readPNG. If you separate the calls, you will see that the call to 
system.file is returning an empty string:

system.file("img", "Seal_Island_Map.png", package="png")
[1] ""

You should then read the help page for function system.file. You do this 
by typing at an R prompt


system.file is looking in directory 'img' for a file named 
Seal_Island_Map.png but in that directory of package png there's just 
one file, RLogo.png. So you have to ask your teacher where to find that 
file, and what function does he use to display it [tip: it's not 
function plot()].

Hope this helps,

Rui Barradas

Em 19-11-2016 18:32, Jackson Hooten escreveu:
> Hello R Help,
> I am fairly new to R and have been scouring the internet trying to find
> useful tips, tricks and advice with how to solve my problems with R. I
> finally was able to find you guys, and am now asking for your help. I have
> a number of different questions regarding R. My most pressing question is,
> how does one get a map of a very specific area into R? I've been following
> a tutorial that one of my teachers sent me and been following his code.
> However, every time I input this code I get a warning message:
> My teacher's code:
>> plot(map, col="dimgray", border=F, add=T)
> The Error code I get every time I input the above code:
>> Error in plot.window(...) : need finite 'ylim' values
> In addition: Warning messages:
> 1: In xy.coords(x, y, xlabel, ylabel, log) : NAs introduced by coercion
> 2: In min(x) : no non-missing arguments to min; returning Inf
> 3: In max(x) : no non-missing arguments to max; returning -Inf
> 4: In plot.window(...) : "border" is not a graphical parameter
> 5: In plot.window(...) : "add" is not a graphical parameter
> So, what I think I figured out was that I didn't possess the "map" that my
> teacher had in his R program. So I went to try and figure out how to get my
> own map into my R session. I found this line of code to try and input a
> good Google Earth map I found that I need for my study. But, alas, this
> code didn't work either and I got more Error codes.
> The code I used:
>> img <-readPNG(system.file("img", "Seal_Island_Map.png", package="png"))
> The Error code I get every time I input the above code:
>> Error in readPNG(system.file("img", "Seal_Island_Map.png",
> package="png")) : unable to open
> For the life of me, I have not been able to find anything anywhere that can
> help me solve these problems. What am I doing wrong? Can you all help?
> Thank you and I hope to talk to you all soon.
> Sincerely,
> Jackson
> 	[[alternative HTML version deleted]]
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