diff --git a/R/GMLLineString.R b/R/GMLLineString.R
index 8abfd64b..a4ad1816 100644
--- a/R/GMLLineString.R
+++ b/R/GMLLineString.R
@@ -37,7 +37,7 @@ GMLLineString <- R6Class("GMLLineString",
     initialize = function(xml = NULL, sfg){
       super$initialize(xml, element = private$xmlElement, wrap = TRUE)
       if(is.null(xml)){
-        if(!is(sfg, c("sfg","XY","LINESTRING"))) stop("Input 'sfg' object should be a 'linestring'")
+        if(!all(sapply(c("sfg","XY", "LINESTRING"), function(x){is(sfg, x)}))) stop("Input 'sfg' object should be a 'linestring'")
         m <- as.matrix(sfg)
         self$posList <- m
         self$setAttr("srsDimension", as.character(dim(m)[2]))
diff --git a/R/GMLMultiCurve.R b/R/GMLMultiCurve.R
index 62dfad64..18679844 100644
--- a/R/GMLMultiCurve.R
+++ b/R/GMLMultiCurve.R
@@ -45,7 +45,7 @@ GMLMultiCurve <- R6Class("GMLMultiCurve",
        super$initialize(xml, element = private$xmlElement, wrap = TRUE)
        if(is.null(xml)){
          if(!is.null(sfg)){
-           if(!is(sfg, c("sfg","XY","MULTILINESTRING"))) stop("Input 'sfg' object should be a 'multilinestring'")
+           if(!all(sapply(c("sfg","XY", "MULTILINESTRING"), function(x){is(sfg, x)}))) stop("Input 'sfg' object should be a 'multilinestring'")
            coords.list <- sfg
            class(coords.list) <- "list"
            for(coords in coords.list){
diff --git a/R/GMLMultiPoint.R b/R/GMLMultiPoint.R
index 5739082c..0b511fbd 100644
--- a/R/GMLMultiPoint.R
+++ b/R/GMLMultiPoint.R
@@ -44,7 +44,7 @@ GMLMultiPoint <- R6Class("GMLMultiPoint",
        super$initialize(xml, element = private$xmlElement, wrap = TRUE)
        if(is.null(xml)){
          if(!is.null(sfg)){
-           if(!is(sfg, c("sfg","XY","MULTIPOINT"))) stop("Input 'sfg' object should be a 'multipoint'")
+           if(!all(sapply(c("sfg","XY", "MULTIPOINT"), function(x){is(sfg, x)}))) stop("Input 'sfg' object should be a 'multipoint'")
            coords.list <- sfg
            class(coords.list) <- "matrix"
            for(i in 1:dim(coords.list)[1]){
diff --git a/R/GMLMultiSurface.R b/R/GMLMultiSurface.R
index e6761b43..f9513556 100644
--- a/R/GMLMultiSurface.R
+++ b/R/GMLMultiSurface.R
@@ -45,7 +45,7 @@ GMLMultiSurface <- R6Class("GMLMultiSurface",
       super$initialize(xml, element = private$xmlElement, wrap = TRUE)
       if(is.null(xml)){
         if(!is.null(sfg)){
-          if(!is(sfg, c("sfg","XY","MULTIPOLYGON"))) stop("Input 'sfg' object should be a 'multipolygon'")
+          if(!all(sapply(c("sfg","XY", "MULTIPOLYGON"), function(x){is(sfg, x)}))) stop("Input 'sfg' object should be a 'multipolygon'")
           coords.list <- sfg
           class(coords.list) <- "list"
           for(coords in coords.list){
diff --git a/R/GMLPoint.R b/R/GMLPoint.R
index 8127e600..4b7b35d4 100644
--- a/R/GMLPoint.R
+++ b/R/GMLPoint.R
@@ -39,7 +39,7 @@ GMLPoint <- R6Class("GMLPoint",
        super$initialize(xml, element = private$xmlElement, wrap = TRUE)
        if(is.null(xml)){
          if(!is.null(sfg)){
-           if(!is(sfg, c("sfg","POINT"))) stop("Input 'sfg' object should be a 'point'")
+           if(!all(sapply(c("sfg","POINT"), function(x){is(sfg, x)}))) stop("Input 'sfg' object should be a 'point'")
            m <- as.matrix(sfg)
          }else if(!is.null(m)){
            if(!is.matrix(m)){
diff --git a/R/GMLPolygon.R b/R/GMLPolygon.R
index 40a0ad5d..f115ac36 100644
--- a/R/GMLPolygon.R
+++ b/R/GMLPolygon.R
@@ -38,7 +38,7 @@ GMLPolygon <- R6Class("GMLPolygon",
     initialize = function(xml = NULL, sfg){
       super$initialize(xml, element = private$xmlElement, wrap = TRUE)
       if(is.null(xml)){
-        if(!is(sfg, c("sfg","XY","POLYGON"))) stop("Input 'sfg' object should be a 'polygon'")
+        if(!all(sapply(c("sfg","XY", "POLYGON"), function(x){is(sfg, x)}))) stop("Input 'sfg' object should be a 'polygon'")
         rings <- sfg
         class(rings) <- "list"
         self$exterior <- GMLLinearRing$new(m=rings[[1]])