To go further with your teacher's code, I would start by finding out what
kind of object "map" is, in R terms. For example, can your teacher give
you the output from the commands:
class(map)
str(map)
?
Without that information, I don't think anyone here can give you effective
help.
Also, as one if the others mentioned, R-sig-geo would be a better place to
ask, when you come back with that information. (And mention up front that
this is not homework, to avoid getting that advice again. Folks will
appreciate it.)
As a general rule, loading images, such as a png file, may or may not
result in an object with correct map coordinates; it depends on the
incoming file.
You could also go back to the CRAN webpage, click on "Task Views" on the
left, then click on "Spatial". There is a LOT of material there. The first
two packages to look at, from my perspective, would be sp and rgdal
(especially if you're going to be doing a lot of serious spatial work in
R) but there are plenty of others that could be relevant for your
particular needs. See also the raster package if your starting point is
really going to be an image such as a png file.
-Don
--
Don MacQueen
Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062
On 11/19/16, 10:32 AM, "R-help on behalf of Jackson Hooten"
<r-help-boun...@r-project.org on behalf of jlhoo...@eckerd.edu> wrote:
>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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>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.
______________________________________________
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