dancefloor_functions.R

creerGrille = function(pol, size=50000) {
  r = raster(extend(extent(pol), size)); res(r) = size; r[]=1
  grille = rasterToPolygons(r)
  grille = grille[which(gIntersects(grille, pol, byid=T)), ]
  grille = grille[-which(gTouches(grille, reg, byid=T)), ]
  return(grille)
}

extractFrequencies = function(grille, r, values) {
  
  counts = extract(clc2, grille, 
                   method="simple", 
                   fun=function(x,...)table(x), 
                   na.rm=T)
  
  mat = matrix(data=0, ncol=5, nrow=nrow(grille))
  if(class(counts)=="list") {
    for (i in 1:length(counts)) {
      mat[i, as.numeric(names(counts[[i]]))] = as.numeric(counts[[i]])
    }  
  } else {
    for (i in as.numeric(colnames(counts))) {
      mat[,i] = counts[,i]  
    }
  }  

  return(mat)
}

makeAtlasLayer = function(pol, colName="size", layerNames) {
  
  out=vector(mode="list", length=length(layerNames))
  for (i in 1:length(layerNames)) {
    f = pol
    f[[colName]] = layerNames[i]
    f = spChFIDs(f, as.character(layerNames[i]))
    out[[i]] = f
  }
  dupreg = do.call(rbind, out)  
  return(dupreg)
}