Thanks. There was a problem with numeric (and factor) ids. Update cartography on your computer:

require(devtools)
devtools::install_github("Groupe-ElementR/cartography")

and it should be ok.

from cartography.

Merci, cela corrige bien le problème que j'avais.
J'ai modifié getGridLayer pour avoir des mailles en projection plane alignées sur le carroyage. Par exemple, pour un pas de 1000 mètres, je voulais avoir les coordonnées des angles en multiple de 1000.
Je mets le code si cela peut servir à d'autres
`getGridLayer2 <- function(spdf, cellsize, spdfid = NULL) {
print(sprintf("getGridLayer2() début"))
if (!requireNamespace("rgeos", quietly = TRUE)) {
stop("'rgeos' package needed for this function to work. Please install it.",
call. = FALSE)
}
print(str(spdf@data))
if (is.null(spdfid)){
spdfid <- names(spdf@data)[1]
}
spdf@data <- spdf@data[spdfid]
row.names(spdf@data)<-spdf@data[,spdfid]
spdf <- spChFIDs(spdf, spdf@data[,spdfid])
spdf@data$area <- rgeos::gArea(spdf, byid=TRUE)

boundingBox <- bbox(spdf)
rounder <- boundingBox %% cellsize
boundingBox[,1] <- boundingBox[,1] - rounder[,1]
roundermax <- cellsize - rounder[,2]
boundingBox[,2] <- boundingBox[,2] + cellsize - rounder[,2]
print(str(boundingBox))
boxCoordX <- seq(from = boundingBox[1,1]-cellsize/2, to = boundingBox[1,2]+cellsize/2, by = cellsize)
boxCoordY <- seq(from = boundingBox[2,1]-cellsize/2, to = boundingBox[2,2]+cellsize/2, by = cellsize)
spatGrid <- expand.grid(boxCoordX, boxCoordY)
spatGrid$id <- seq(1, nrow(spatGrid), 1)
coordinates(spatGrid) <- 1:2 # promote to SpatialPointsDataFrame
gridded(spatGrid) <- TRUE # promote to SpatialPixelsDataFrame
spgrid <- methods::as(spatGrid, "SpatialPolygonsDataFrame") # promote to SpatialPolygonDataFrame

proj4string(spgrid) <-proj4string(spdf)
row.names(spgrid) <- as.character(spgrid$id)

On ne garde que ce qui touche le fond de carte initial

over <- rgeos::gIntersects(spgrid, spdf, byid = TRUE)
x <- colSums(over)
spgrid <- spgrid[spgrid$id %in% names(x[x>0]),]

mask <- rgeos::gBuffer(spdf, byid=FALSE, id=NULL, width=1.0, quadsegs=5, capStyle="ROUND",joinStyle="ROUND", mitreLimit=1.0)
spgrid <- rgeos::gIntersection(spgrid, mask, byid=TRUE, id=as.character(spgrid@data$id), drop_lower_td=FALSE)
data <- data.frame(id=sapply(methods::slot(spgrid, "polygons"), methods::slot, "ID"))
row.names(data) <- data$id
spgrid<-SpatialPolygonsDataFrame(spgrid, data)
spgrid@data$cell_area <- rgeos::gArea(spgrid, byid=TRUE)
proj4string(spgrid) <-proj4string(spdf)

On calcule la table de passage

intersection

parts <- rgeos::gIntersection(spgrid, spdf, byid=TRUE,drop_lower_td=TRUE)
data <- data.frame(id=sapply(methods::slot(parts, "polygons"), methods::slot, "ID"))
tmp <- data.frame(do.call('rbind', (strsplit(as.character(data$id)," "))))
data$id1 <- as.vector(tmp$X1)
data$id2 <- as.vector(tmp$X2)
row.names(data)<-data$id
parts<-SpatialPolygonsDataFrame(parts, data)
proj4string(parts) <-proj4string(spdf)

Part de surface intersectée

parts@data$area_part <- rgeos::gArea(parts, byid=TRUE)
parts@data <- data.frame(parts@data, area_full=spdf@data[match( parts@data$id2, spdf@data[,spdfid]),"area"])
parts@data$area_pct <- (parts@data$area_part/parts@data$area_full)*100
areas <- parts@data[,c("id1","id2","area_pct")]
colnames(areas) <- c("id_cell","id_geo","area_pct")
return(list(spdf = spgrid, df = areas))
}`

from cartography.

merci

from cartography.