[R] ggmap (or ggplot2 with mapping question)

David Winsemius dwinsemius at comcast.net
Sat Dec 27 01:16:57 CET 2014


> On Dec 26, 2014, at 3:26 PM, Roy Mendelssohn - NOAA Federal <roy.mendelssohn at noaa.gov> wrote:
> 
> HI All:
> 
> Okay I am feeling particular brain dead today.  i have the following map created so far using ggmap:
> 
>> library(ggmap)
>> myLocation <- c(-178, -28, -72, 48)
>> myMap <- get_map(location=myLocation, source="google", maptype="satellite", crop=FALSE)
>> 

All if get is a matrix. No map.


> 
> I want to color in some lat-lon 5 degree boxes based on some criterion,  and it look like this could be done use geom_polygon if I can figure out how to get the data in the format required for geom_polygon.  To simplify the problem, suppose i have a bounding box:
> 
> subbox<-c(-130, 20, -125, 25)
> 

That looks more like a specification for geom.rect than for geom_polygon.

 
> and I want to color that box red on myMap defined above.    To put this in context, I actually have 360 squares which have been clustered by some criteria, and I want to color them all based on the cluster number of the box. but if I can figure out how to do the simple problem above I can  extend it to the more general problem.
> 
> Basically the question is how can I get that simple box information into the format required for eom_polygon.

If it were used for eom_polygon I would imagine you need to put it in the form pairs (x,y)

subbox<-list(x=c(-130,-125,-125,-130,-130),y=c( 20,20,25, 25,20))

Just a guess mind, you.

— 
David.
> 
> Thanks for any help.
> 
> -Roy
> 
> 
> **********************
> "The contents of this message do not reflect any position of the U.S. Government or NOAA."
> **********************
> Roy Mendelssohn
> Supervisory Operations Research Analyst
> NOAA/NMFS



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