position de légende

[Eric Pagot]

Bonjour,

Je cherche un moyen pour déterminer la place d'une légende sans la superposer au graphique. je prend un exemple :
x<-c(39,39.8,39.2,39.2,39,38.6,38.6,39.1,39.3,38.9,39.1,40,38.8,39.4,39.2,39.3,39.3,38.9,39.9,38.2,39.2,38.8,39.9,39.6,39.4,40.8,39.4,38.9,39.2,38.8,39.6,38.6,38.9,38.7,38.8,39.7,38.7,40.6,39.1,39.7,38.6,40.1,39,39.4,39.4,39.3,38.8,39.1,38.9,38.7,39.3,38.9,39.9,39.2,41.8,39.6,39.2,39.1,39.5,40.2,39.2,38.4,39.4,39.2,40.1,39.6,38.4,41.3,39.3,39.7,39.7,40.4,38.9,38.6,39.5,39.6,41.2,39.4,38.2,39.7,39.9,39.1,38.2,39.5,39.8,42.1,39.4,39.7,39.9,40.5,39.3,41.2,38.1)
y<-c(39.4,39,38.7,38.3,40.6,39.1,39.1,39.5,41.7,39.5,39,40.1,39.2,39.2,39.6,39.2,39.7,39.4,39.2,39.4,39.4,39.2,39.1,38.9,38.4,39.6,39.2,39.3,39.2,39.2,39.2,38.5,39.9,38.7,38.6,38.8,38.3,40.2,38.5,39.5,38.4,40.1,39.1,38.4,39.5,39.3,38.8,40.5,40.1,38.9,38.9,39.1,39.9,39.7,39,40,39.7,39.7,39.3,40.5,39.7,39.3,38.9,39.2,40.5,40.2,39.2,41,38.9,39.4,38.8,39.8,40.2,38.5,39.6,39.3,38.7,39.2,38.1,40.1,38.6,39.2,39.4,39.9,39.8,39.5,39.1,40.5,39.7,39.6,38.5,39.9,38.1)
Si l'on fait le dessin, la légende peut être mise en haut ou en bas à droite mais pas en bas à gauche (donc tout sauf "bottomleft").Je pense qu'il doit y avoir moyen de calculer l'endroit où la légende écrite ne se superpose pas au dessin (la largeur de la légende doit aussi jouer). Si quelqu'un a des pistes...

[Logez Maxime]

Bonjour,

Une piste comme une autre, tu calcules la distance entre tes points et les coins de la figure et les coins qui présentent la plus grande distance alors sont des candidats pour disposer ta légende :

Code : Tout sélectionner

plot(x,y)
coins <- expand.grid(par()$usr[1:2],par()$usr[3:4])
coins <- as.matrix(coins)
colnames(coins) <- c("x","y")

coins
         x      y
[1,] 37.94 37.956 # en bas à gauche
[2,] 42.26 37.956 #en bas à droite
[3,] 37.94 41.844 #en haut à gauche
[4,] 42.26 41.844 # en haut à droite

# la plus petite distance entre un des points et les coins
apply(coins,1,function(w) min(rowSums(sweep(X,2,w,"-")^2)))
[1] 0.046336 1.301536 1.870336 1.633936

Il est clair ici que le coin en bas a gauche n'est pas le bon candidat, il semblerai que ce soit en haut à gauche que tu es le plus de place pour la légende. Après il te faut avoir la taille de la légende pour savoir quelles sont les coins qui peuvent la contenir.

Maxime

[Olivier Delaigue]

En marge du graphe, il n'y a jamais de problème ;-)

[Eric Pagot]

Merci pour le calcul de distance, je vais pouvoir utiliser la formule. En fait, j'avais besoin de cela pour mettre dans un dessin avec de multiples fenêtres.