Re: [R] Help with map
On Sat, 5 May 2007, Alberto Vieira Ferreira Monteiro wrote:
> [for those that worry about these things, this _is_ a homework
> assignment. However, it's not an R homework, it's a Geography
> and History homework... and I want to use R to create a pretty
> map]
>
> Roger Bivand wrote:
> >
> >> Is there any way to associate one color to each country?
> >
> > Try:
> >
> > map_poly_obj <- map("worldHires", c("Argentina", "Brazil"), plot=FALSE,
> > fill=TRUE)
> > str(map_poly_obj)
> >
> > and you'll see that the component of interest is the named polygons, of
> > which there are 28, namely
> >
> Ok, I guess I can see what you mean. It worked, but I don't think
> this is a practical way to draw things.
>
> For example, suppose [this would help homework mentioned above] I
> want to draw a series of maps showing the evolution of Communism
> in the XX century. I would like to start with a 1917 map, showing most
> countries as in...
>
> map("worldHires")
>
> ... but with the Soviet Union in red. I don't see how I could mix the two
> maps (BTW, there's no Russia in worldHires, but there is a USSR...)
>
> map("worldHires"); map("worldHires", "USSR", col="red", fill=T)
[Please note that the worldHires database refers to a particular time
cross section, probably late 1980's. The territorial extents of the former
USSR in 1919, 1920, 1939, 1940, 1941, 1944, 1945, etc., etc. are not the
same; the same consideration would apply to PRC's actual control over
Tibet.
So to do this, you need a sequence of maps showing the marginal
increments, with 1917 actually only colouring Petrograd/St Petersburg and
perhaps some other cities. I'm not aware of any publically available
sequence of boundary files adequately representing the situation of say
the Baltic states or Finland for the 1917-2007 period, if anyone has a
suitable link, please say so.
Geographical data are vintaged, not just "where", but "where when". Was
for example Estonia occupied by the USSR 1940-1941, 1944-1991, or was it
part of the USSR for the purposes of this exercise? Using disputed
boundaries implies a choice of point of view, one that may not be
intended.]
Roger
>
> >
> > map_poly_obj$names
> >
> > So you can build a matching colours vector, or:
> >
> > library(sp)
> > library(maptools)
> > IDs <- sapply(strsplit(map_poly_obj$names, ":"), function(x) x[1])
> > SP_AB <- map2SpatialPolygons(map_poly_obj, IDs=IDs,
> > proj4string=CRS("+proj=longlat +datum=wgs84"))
> >
> > but
> >
> > plot(SP_AB, col=c("cyan", "green"))
> >
> > still misses, because some polygons have their rings of coordinates in
> > counter-clockwise order, so:
> >
> > pl_new <- lapply(slot(SP_AB, "polygons"), checkPolygonsHoles)
> > slot(SP_AB, "polygons") <- pl_new
> > # please forget the assignment to the slot and do not do it unless you can
> > # replace what was there before
> >
> > plot(SP_AB, col=c("cyan", "green"), axes=TRUE)
> >
> > now works. Moreover, SP_AB is a SpatialPolygons object, which can be
> > promoted to a SpatialPolygonsDataFrame object, for a data slot holding a
> > data.frame with row names matching the Polygons ID values:
> >
> > sapply(slot(SP_AB, "polygons"), function(x) slot(x, "ID"))
> >
> > So adding a suitable data frame gets you to the lattice graphics method
> >
> > spplot(SP_AB, "my_var")
> >
> > Hope this helps,
> >
> So, in the above mentioned case, I could do something like:
>
> library(mapdata)
> commies <- c("USSR", "Mongolia")
> # Mongolia was the 2nd communist country, in 1925
> map_poly_obj <- map("worldHires", plot=FALSE)
> map_poly_commies <- map("worldHires", commies,
> plot=FALSE, fill=TRUE)
> plot(map_poly_obj, type="l")
> polygon(map_poly_commies, col="red", border="black")
>
> I guess I can keep going, unless there is a simpler solution.
>
> Alberto Monteiro
>
--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: [EMAIL PROTECTED]
__
R-help@stat.math.ethz.ch 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] Help with map
On 04/05/2007 9:00 PM, Alberto Vieira Ferreira Monteiro wrote:
> [for those that worry about these things, this _is_ a homework
> assignment. However, it's not an R homework, it's a Geography
> and History homework... and I want to use R to create a pretty
> map]
>
> Roger Bivand wrote:
>>> Is there any way to associate one color to each country?
>> Try:
>>
>> map_poly_obj <- map("worldHires", c("Argentina", "Brazil"), plot=FALSE,
>> fill=TRUE)
>> str(map_poly_obj)
>>
>> and you'll see that the component of interest is the named polygons, of
>> which there are 28, namely
>>
> Ok, I guess I can see what you mean. It worked, but I don't think
> this is a practical way to draw things.
>
> For example, suppose [this would help homework mentioned above] I
> want to draw a series of maps showing the evolution of Communism
> in the XX century. I would like to start with a 1917 map, showing most
> countries as in...
>
> map("worldHires")
>
> ... but with the Soviet Union in red. I don't see how I could mix the two
> maps (BTW, there's no Russia in worldHires, but there is a USSR...)
>
> map("worldHires"); map("worldHires", "USSR", col="red", fill=T)
>
>> map_poly_obj$names
>>
>> So you can build a matching colours vector, or:
>>
>> library(sp)
>> library(maptools)
>> IDs <- sapply(strsplit(map_poly_obj$names, ":"), function(x) x[1])
>> SP_AB <- map2SpatialPolygons(map_poly_obj, IDs=IDs,
>> proj4string=CRS("+proj=longlat +datum=wgs84"))
>>
>> but
>>
>> plot(SP_AB, col=c("cyan", "green"))
>>
>> still misses, because some polygons have their rings of coordinates in
>> counter-clockwise order, so:
>>
>> pl_new <- lapply(slot(SP_AB, "polygons"), checkPolygonsHoles)
>> slot(SP_AB, "polygons") <- pl_new
>> # please forget the assignment to the slot and do not do it unless you can
>> # replace what was there before
>>
>> plot(SP_AB, col=c("cyan", "green"), axes=TRUE)
>>
>> now works. Moreover, SP_AB is a SpatialPolygons object, which can be
>> promoted to a SpatialPolygonsDataFrame object, for a data slot holding a
>> data.frame with row names matching the Polygons ID values:
>>
>> sapply(slot(SP_AB, "polygons"), function(x) slot(x, "ID"))
>>
>> So adding a suitable data frame gets you to the lattice graphics method
>>
>> spplot(SP_AB, "my_var")
>>
>> Hope this helps,
>>
> So, in the above mentioned case, I could do something like:
>
> library(mapdata)
> commies <- c("USSR", "Mongolia")
> # Mongolia was the 2nd communist country, in 1925
> map_poly_obj <- map("worldHires", plot=FALSE)
> map_poly_commies <- map("worldHires", commies,
> plot=FALSE, fill=TRUE)
> plot(map_poly_obj, type="l")
> polygon(map_poly_commies, col="red", border="black")
>
> I guess I can keep going, unless there is a simpler solution.
Here's the sloppy code I used to put together the map in the persp3d
example in rgl 0.71. I've just made a few edits; I hope it still runs.
The idea is to do a lot of calculations on a vector of colours, then
plot them all at once.
> library(mapdata)
>
> names <- map("worldHires", plot=FALSE, namesonly=TRUE)
> countries <- gsub(":.*", "", names) # the first part of the name
> lakes <- grep("Lake", names)
> lakes <- lakes[-15]
> lakes <- unique(c(lakes, grep("Ozero", names),
> grep("Vodokh", names),
> grep("Nuur", names),
> grep("Ostrov Ol'khon", names),
> grep("Hayk", names),
> grep("Lago", names))) # The map doesn't distinguish
> these
>
> seas <- grep("Sea", names)
> nfld <- grep("^Newfoundland$", names) # nfld should be coloured as Canada
> canada <- grep("^Canada$", names)
> svalbard <- grep("Svalbard", names) # Svalbard coloured as Norway
> norway <- grep("^Norway$", names)
>
> nums <- as.numeric(factor(countries))
> N <- max(nums)
> set.seed(3)
> col <- hcl(h=sample((1:N)*360/N),
> c=sample(seq(35,45,len=N)),
> l=sample(seq(75,85,len=N)))[nums] # random colours by country
> col[c(lakes,seas)] <- "white" # with lakes and seas white
> col[nfld] <- col[canada]
> col[svalbard] <- col[norway]
>
> png(width=2200, height=2200, file='world.png')
> map('worldHires', fill = TRUE, col = col, ylim=c(-90,90))
> abline(h=c(-90, 90))
> abline(v=c(-180.05, 180.05))
> dev.off()
I hope this gives you some ideas.
Duncan Murdoch
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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Re: [R] Help with map
[for those that worry about these things, this _is_ a homework
assignment. However, it's not an R homework, it's a Geography
and History homework... and I want to use R to create a pretty
map]
Roger Bivand wrote:
>
>> Is there any way to associate one color to each country?
>
> Try:
>
> map_poly_obj <- map("worldHires", c("Argentina", "Brazil"), plot=FALSE,
> fill=TRUE)
> str(map_poly_obj)
>
> and you'll see that the component of interest is the named polygons, of
> which there are 28, namely
>
Ok, I guess I can see what you mean. It worked, but I don't think
this is a practical way to draw things.
For example, suppose [this would help homework mentioned above] I
want to draw a series of maps showing the evolution of Communism
in the XX century. I would like to start with a 1917 map, showing most
countries as in...
map("worldHires")
... but with the Soviet Union in red. I don't see how I could mix the two
maps (BTW, there's no Russia in worldHires, but there is a USSR...)
map("worldHires"); map("worldHires", "USSR", col="red", fill=T)
>
> map_poly_obj$names
>
> So you can build a matching colours vector, or:
>
> library(sp)
> library(maptools)
> IDs <- sapply(strsplit(map_poly_obj$names, ":"), function(x) x[1])
> SP_AB <- map2SpatialPolygons(map_poly_obj, IDs=IDs,
> proj4string=CRS("+proj=longlat +datum=wgs84"))
>
> but
>
> plot(SP_AB, col=c("cyan", "green"))
>
> still misses, because some polygons have their rings of coordinates in
> counter-clockwise order, so:
>
> pl_new <- lapply(slot(SP_AB, "polygons"), checkPolygonsHoles)
> slot(SP_AB, "polygons") <- pl_new
> # please forget the assignment to the slot and do not do it unless you can
> # replace what was there before
>
> plot(SP_AB, col=c("cyan", "green"), axes=TRUE)
>
> now works. Moreover, SP_AB is a SpatialPolygons object, which can be
> promoted to a SpatialPolygonsDataFrame object, for a data slot holding a
> data.frame with row names matching the Polygons ID values:
>
> sapply(slot(SP_AB, "polygons"), function(x) slot(x, "ID"))
>
> So adding a suitable data frame gets you to the lattice graphics method
>
> spplot(SP_AB, "my_var")
>
> Hope this helps,
>
So, in the above mentioned case, I could do something like:
library(mapdata)
commies <- c("USSR", "Mongolia")
# Mongolia was the 2nd communist country, in 1925
map_poly_obj <- map("worldHires", plot=FALSE)
map_poly_commies <- map("worldHires", commies,
plot=FALSE, fill=TRUE)
plot(map_poly_obj, type="l")
polygon(map_poly_commies, col="red", border="black")
I guess I can keep going, unless there is a simpler solution.
Alberto Monteiro
__
R-help@stat.math.ethz.ch 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.
Re: [R] Help with map
On Fri, 4 May 2007, Alberto Monteiro wrote:
> I have just learned how to play with map, but something weird
> (or not) is happening.
>
> Suppose I want to draw a map of two countries (that have disconnected
> components), like Argentina and Brazil.
>
> If I command:
>
> library(maps)
> library(mapdata)
> map("worldHires", c("Argentina", "Brazil"))
>
> It works fine. However, if I want to _colour_ the interior:
>
> map("worldHires", c("Argentina", "Brazil"), c("cyan", "green"), fill=T)
>
> Then the colors will be assigned to the islands (Marajo in Brazil's
> North and Tierra del Fuego in Argentina's South) and there will be
> a recycling.
>
> Is there any way to associate one color to each country?
Try:
map_poly_obj <- map("worldHires", c("Argentina", "Brazil"), plot=FALSE,
fill=TRUE)
str(map_poly_obj)
and you'll see that the component of interest is the named polygons, of
which there are 28, namely
map_poly_obj$names
So you can build a matching colours vector, or:
library(sp)
library(maptools)
IDs <- sapply(strsplit(map_poly_obj$names, ":"), function(x) x[1])
SP_AB <- map2SpatialPolygons(map_poly_obj, IDs=IDs,
proj4string=CRS("+proj=longlat +datum=wgs84"))
but
plot(SP_AB, col=c("cyan", "green"))
still misses, because some polygons have their rings of coordinates in
counter-clockwise order, so:
pl_new <- lapply(slot(SP_AB, "polygons"), checkPolygonsHoles)
slot(SP_AB, "polygons") <- pl_new
# please forget the assignment to the slot and do not do it unless you can
# replace what was there before
plot(SP_AB, col=c("cyan", "green"), axes=TRUE)
now works. Moreover, SP_AB is a SpatialPolygons object, which can be
promoted to a SpatialPolygonsDataFrame object, for a data slot holding a
data.frame with row names matching the Polygons ID values:
sapply(slot(SP_AB, "polygons"), function(x) slot(x, "ID"))
So adding a suitable data frame gets you to the lattice graphics method
spplot(SP_AB, "my_var")
Hope this helps,
Roger
>
> Alberto Monteiro
>
> __
> R-help@stat.math.ethz.ch 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.
>
--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: [EMAIL PROTECTED]
__
R-help@stat.math.ethz.ch 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 with map
I have just learned how to play with map, but something weird
(or not) is happening.
Suppose I want to draw a map of two countries (that have disconnected
components), like Argentina and Brazil.
If I command:
library(maps)
library(mapdata)
map("worldHires", c("Argentina", "Brazil"))
It works fine. However, if I want to _colour_ the interior:
map("worldHires", c("Argentina", "Brazil"), c("cyan", "green"), fill=T)
Then the colors will be assigned to the islands (Marajo in Brazil's
North and Tierra del Fuego in Argentina's South) and there will be
a recycling.
Is there any way to associate one color to each country?
Alberto Monteiro
__
R-help@stat.math.ethz.ch 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.
