[R] colored maps again

[Alina Sheyman]

I'm trying to create a colored map that would show the number of students
per state.
My data frame consists of two columns - state and count.
I'm using the following code

library(maps)
map(usa)
library(plotrix)
state.col-color.scale(gre$count,0,0,c(0,1))
 map(state,fill=TRUE,col=state.col)

I'm getting a map, but the values are not being mapped to correct states.
What do I need to do to fix that?

[[alternative HTML version deleted]]

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Re: [R] colored maps again

[Mike Lawrence]

Here's a bit of a hacky way to do it:


#get the names of each state
state=map('state',plot=F)$names

#set up some random state-color data
cols = 
as.data.frame(cbind(state=states,x=sample(1:10,length(states),replace=T)))

#do the plot
map('usa')
for(this_state in state){

map('state',region=this_state,add=T,fill=T,col=cols$x[cols$state==this_state])
}



On Thu, Feb 19, 2009 at 12:45 PM, Alina Sheyman alina...@gmail.com wrote:
 I'm trying to create a colored map that would show the number of students
 per state.
 My data frame consists of two columns - state and count.
 I'm using the following code

 library(maps)
 map(usa)
 library(plotrix)
 state.col-color.scale(gre$count,0,0,c(0,1))
  map(state,fill=TRUE,col=state.col)

 I'm getting a map, but the values are not being mapped to correct states.
 What do I need to do to fix that?

[[alternative HTML version deleted]]

 __
 R-help@r-project.org mailing list
 https://stat.ethz.ch/mailman/listinfo/r-help
 PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
 and provide commented, minimal, self-contained, reproducible code.




-- 
Mike Lawrence
Graduate Student
Department of Psychology
Dalhousie University
www.thatmike.com

Looking to arrange a meeting? Check my public calendar:
http://www.thatmike.com/mikes-public-calendar

~ Certainty is folly... I think. ~

__
R-help@r-project.org mailing list
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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.

Re: [R] colored maps again

[Greg Snow]

The problem is that the order and number of polygons in map does not match your 
data (most likely).

Try:

library(maps)
library(plotrix)
state.col-color.scale(state.x77[,'HS Grad'],0,0,c(0,1))
 map(state,fill=TRUE,col=state.col)

nms - map('state', plot=FALSE)$names
nms - sub(':.*$','',nms)
ind - match(nms, tolower(state.name))

map('state', fill=TRUE, col=state.col[ind])

Now try it with your data, just replace state.name with the names of the states 
in the order of your data if it is different (possibly the rownames).

You may also want to look at state.vbm in the TeachingDemos package (works with 
maptools rather than maps) as another way to plot colored maps of the USA that 
is less affected by geographical area.

Hope this helps,

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.s...@imail.org
801.408.8111


 -Original Message-
 From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-
 project.org] On Behalf Of Alina Sheyman
 Sent: Thursday, February 19, 2009 9:46 AM
 To: r-help@r-project.org
 Subject: [R] colored maps again
 
 I'm trying to create a colored map that would show the number of
 students
 per state.
 My data frame consists of two columns - state and count.
 I'm using the following code
 
 library(maps)
 map(usa)
 library(plotrix)
 state.col-color.scale(gre$count,0,0,c(0,1))
  map(state,fill=TRUE,col=state.col)
 
 I'm getting a map, but the values are not being mapped to correct
 states.
 What do I need to do to fix that?
 
   [[alternative HTML version deleted]]
 
 __
 R-help@r-project.org mailing list
 https://stat.ethz.ch/mailman/listinfo/r-help
 PLEASE do read the posting guide http://www.R-project.org/posting-
 guide.html
 and provide commented, minimal, self-contained, reproducible code.

__
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.