[R] adjusting the map of France to 1830

[Michael Friendly]

Here's what I tried.   I can plot a selection of regions, but I
can't seem to remove an arbitrary list of region numbers, unless I've 
done something wrong
by selecting the regions I want to plot with departements[-exclude].
I also get an error
when I try to use map.text to label a map with only the regions I'm  
selecting.

 > departements <- map('france',namesonly=T, plot=FALSE)
 > # returns a vector of names of regions
 >
 > exclude <- c(47,  #Alpes-Maritimes
+ 66,  # Haute-Savoie
+ 76,  # Savoie
+ 95,  # Territore-de-Belfort
+ 109, 110, 111, # Var: Iles d'Hyeres
+ 49, 53, 54, 55, # Moribhan: Isles
+ 62, 64,    # Vendee: Isles
+ 72, 75     # Charente-Maritime: Isles
+ )
 >
 > depts <- departements[-exclude]
 > gfrance <-map('france', regions=depts)
 > labels <- (as.character(1:length(departements)))[-exclude]
 > gfrance <-map.text('france', regions=depts, add=FALSE, labels=labels)
Error in map.text("france", regions = depts, add = FALSE, labels = labels) :
        map object must have polygons (fill=TRUE)

Another problem, potentially more difficult for mapping data on the map 
of France is that
the "departements" are actually just the polygons in the map, 
arbitrarily numbered from
east to west, and from north to south --- they don't correspond to the 
'official' administrative
region numbers.  As well, the departement names don't always match 
exactly (ignoring
accents, e.g., Val-d'Oise vs. Val-Doise) so it would be another 
challenge to plot my
historical data on the map of France.

-Michael


Stephane DRAY wrote:

> Hello. I do not know if you can merge polygons, but you can select 
> easily:
>
> > departements=map('france',namesonly=T) # returns a vector of names 
> of regions
> > map('france',regions=departements[1:20],namesonly=T) # use what you 
> need with regions argument
>
> Hope this helps,
>
>
> At 16:29 18/11/2004, Michael Friendly wrote:
>
>> I'm doing some analyses of historical data from France in 1830 on 
>> 'moral statistics' that I'd like to
>> show on a map.  I've done most of my analyses in SAS, but a few 
>> things would work better in R.
>> To do this, I have to adjust the modern map,
>>
>> library(maps)
>> map('france')
>>
>> to adjust for changes in departments (86 in 1830, to 97 now).  I've 
>> read the documentation
>> for the maps and maptools package, but there seems to be no functions 
>> to allow this, and
>> I can't find information on the exact structure of map datasets, but 
>> I understand them to
>> be delimited lists of polygon coordinates.
>>
>> In SAS, all maps have (one or more) ID variables representing the 
>> geographical region,
>> and there is also a proc gremove that can remove internal boundaries 
>> inside the polygons
>> for regions with the same ID.  Is there some way I can do this in R?
>>
>> Here's what I did in SAS:
>>
>> *-- Fix the map of France to conform to Guerry:
>>    - adjust the 97 current departments to correspond to the 86 in 1830
>>    - delete those not part of France then
>> ;
>>
>> data gfrtemp;
>>    set maps.france;
>>    /* Corse was one dept - merge these to one area, new ID */
>>    if id in (201, 202)    then dept=200;
>>
>>    /* Seine et Oise (78) was cut into
>>    Essonne (91), Val d'Oise (95) and Yvelines (78) */
>>    else if id in (91, 95)    then dept=78;
>>
>>    /* Seine (75) now split into
>>    Hauts-de-Seine (92), Seine-Saint-Denis (93) et Val-de-Marne (94)*/
>>    else if id in (92, 93, 94)    then dept=75;
>>
>>     /* departments not part of France in 1830 */
>>    else if id in (
>>        6,     /* Alpes-Maritimes */
>>        73,74, /* Savoie, Haute-Savoie */
>>        90)    /* Territore-de-Belfort */
>>        then delete;
>>    else                       dept=id;
>>    run;
>>
>> *-- remove internal boundaries based on merged DEPT;
>> proc sort data=gfrtemp;
>>    by dept;
>>
>> proc gremove data=gfrtemp out=gfrance;
>>   by dept;
>>   id id;
>>   run;
>>
>>
>>
>> -- 
>> Michael Friendly     Email: friendly at yorku.ca Professor, Psychology 
>> Dept.
>> York University      Voice: 416 736-5115 x66249 Fax: 416 736-5814
>> 4700 Keele Street    http://www.math.yorku.ca/SCS/friendly.html
>> Toronto, ONT  M3J 1P3 CANADA
>>
>> ______________________________________________
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>> http://www.R-project.org/posting-guide.html
>
>
> Stéphane DRAY
> -------------------------------------------------------------------------------------------------- 
>
> Département des Sciences Biologiques
> Université de Montréal, C.P. 6128, succursale centre-ville
> Montréal, Québec H3C 3J7, Canada
>
> Tel : (514) 343-6111 poste 1233         Fax : (514) 343-2293
> E-mail : stephane.dray at umontreal.ca
> -------------------------------------------------------------------------------------------------- 
>
> Web                                          
> http://www.steph280.freesurf.fr/
> -------------------------------------------------------------------------------------------------- 
>
>


-- 
Michael Friendly     Email: friendly at yorku.ca 
Professor, Psychology Dept.
York University      Voice: 416 736-5115 x66249 Fax: 416 736-5814
4700 Keele Street    http://www.math.yorku.ca/SCS/friendly.html
Toronto, ONT  M3J 1P3 CANADA