[R] merging df with world map

[MacQueen, Don]

And you can check what David and Jeff suggested like this:

intersect( df$COUNTRY, world_map$region )

If they have any values in common, that command will show them. (Note that
I said values in common, not countries in common.)

WARNING:
It appears that you have each country appearing more than once in both of
the data frames. Even if the country names were spelled the same (which
they are not in the first few rows), I would not care to predict the
outcome of a many-to-many merge. It probably won't make sense for showing
the data on a map.

-Don

-- 
Don MacQueen

Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062





On 6/17/16, 1:06 PM, "R-help on behalf of ch.elahe via R-help"
<r-help-bounces at r-project.org on behalf of r-help at r-project.org> wrote:

>Hi all,
>I want to use world map in ggplot2 and show my data on world map. my df
>is:
>
>
>    $ COUNTRY           : chr  "DE" "DE" "FR" "FR" ..
>
>    $ ContrastColor     : int  9 9 9 9 13 9 9 9 9 ..
>
>    $ quant             : Factor w/ 4 levels "FAST","SLOW",..I need to
>merge my df with world_map data which is like this:
>
>    
>    world_map=map_data("world")
>    data.frame':   99338 obs. of  6 variables:
>    $ long     : num  -69.9 -69.9 -69.9 -70 -70.1 ...
>    $ lat      : num  12.5 12.4 12.4 12.5 12.5 ...
>    $ group    : num  1 1 1 1 1 1 1 1 1 1 ...
>    $ order    : int  1 2 3 4 5 6 7 8 9 10 ...
>    $ region   : chr  "Aruba" "Aruba" "Aruba" "Aruba" ...
>    $ subregion: chr  NA NA NA NA ...
>but by merging my df with world map data I get a data frame with zero
>observation in it,I use this command for merging:
>
>
>    world_map=merge(world_map,df,by.x="region",by.y="COUNTRY")
>    str(world_map)
>
>    'data.frame':   0 obs. of  133 variables:
>    $ region            : chr
>    $ long              : num
>    $ lat               : num
>    $ group             : num
>    $ order             : int
>    $ subregion         : chr
>does anyone know what is the problem of this merging that I am currently
>using?
>thanks for any help!
>Elahe
>
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