diff --git a/R/step2_helper_data.R b/R/step2_helper_data.R
index 17f0039a..effff2c5 100644
--- a/R/step2_helper_data.R
+++ b/R/step2_helper_data.R
@@ -284,16 +284,16 @@ getdts = function(aes, unm, p, q, o, dt, shpvars, layer, mfun, args, plot.order)
 							   submit_legend = TRUE)
 				if (!all(dtl$sel__)) {
 					if (bypass_ord) {
-						dtl[, c(varname, legname, crtname) := list(value.null, 0L)]
+						dtl[, c(varname, legname, crtname) := list(value.null, 0L, 0L)]
 					} else {
-						dtl[, c(varname, ordname, legname, crtname) := list(value.null, -1L, 0L)]	
+						dtl[, c(varname, ordname, legname, crtname) := list(value.null, -1L, 0L, 0L)]	
 					}
 					
 					if (is.na(value.null)) stop("value.null not specified for aesthetic ", nm, call. = FALSE)
 					if (bypass_ord) {
-						dtl[sel__ == TRUE, c(varname, legname) := do.call(f, c(unname(.SD), arglist)), grp_b_fr, .SDcols = v]
+						dtl[sel__ == TRUE, c(varname, legname, crtname) := do.call(f, c(unname(.SD), arglist)), grp_b_fr, .SDcols = v]
 					} else {
-						dtl[sel__ == TRUE, c(varname, ordname, legname) := do.call(f, c(unname(.SD), arglist)), grp_b_fr, .SDcols = v]
+						dtl[sel__ == TRUE, c(varname, ordname, legname, crtname) := do.call(f, c(unname(.SD), arglist)), grp_b_fr, .SDcols = v]
 					}
 				} else {
 					if (bypass_ord) {
@@ -308,7 +308,6 @@ getdts = function(aes, unm, p, q, o, dt, shpvars, layer, mfun, args, plot.order)
 					names(levs) = grp_bv
 					dtl = completeDT2(dtl, cols = c(list("tmapID__" = unique(dtl$tmapID__)), levs), defs = imp)
 				}
-
 				dtl
 			}
 			
diff --git a/R/tm_layers_cartogram.R b/R/tm_layers_cartogram.R
index 0e5a305c..91412795 100644
--- a/R/tm_layers_cartogram.R
+++ b/R/tm_layers_cartogram.R
@@ -1,3 +1,41 @@
+#' @rdname tm_cartogram
+#' @name opt_tm_cartogram
+#' @export
+opt_tm_cartogram = function(type = "cont",
+							itermax = 15,
+							...) {
+	list(cartogram = list(mapping.args = list(),
+						 trans.args = list(type = type, itermax = itermax)),
+		  polygons = do.call(opt_tm_polygons, list(...)))
+}
+
+#' @rdname tm_cartogram
+#' @name opt_tm_cartogram
+#' @export
+opt_tm_cartogram_ncont = function(type = "ncont",
+								  expansion = 1,
+								  inplace = FALSE,
+								  ...) {
+	
+	list(cartogram = list(mapping.args = list(),
+						  trans.args = list(type = type, expansion = expansion, inplace = inplace)),
+		 polygons = do.call(opt_tm_polygons, list(...)))
+}
+
+
+#' @rdname tm_cartogram
+#' @name opt_tm_cartogram
+#' @export
+opt_tm_cartogram_dorling = function(type = "dorling",
+									share = 5,
+									itermax = 1000,
+									...) {
+	list(cartogram = list(mapping.args = list(),
+						  trans.args = list(type = type, share = share, itermax = itermax)),
+		 polygons = do.call(opt_tm_polygons, list(...)))
+}
+
+
 #' Map layer: cartogram
 #' 
 #' Map layer that draws a cartogram
@@ -6,7 +44,7 @@
 #'   determines the size of the polygons.
 #' @param plot.order Specification in which order the spatial features are drawn.
 #'   See [tm_plot_order()] for details.
-#' @param trans.args lists that are passed on to internal transformation function
+#' @param options options passed on to the corresponding `opt_<layer_function>` function 
 #' @inheritDotParams tm_polygons
 #' @export
 tm_cartogram = function(size = 1,
@@ -15,17 +53,17 @@ tm_cartogram = function(size = 1,
 						size.chart = tm_chart_none(),
 						size.free = NA,
 						plot.order = tm_plot_order("size", reverse = FALSE),
-						trans.args = list(type = "cont", itermax = 15),
+						options = opt_tm_cartogram(),
 						...) {
 	po = plot.order
 	#trans.args$type = match.arg(trans.args$type)
 	
 	# types: "cont", "ncont", "dorling"
 	
-	tmp = do.call(tm_polygons, list(...))
+	tmp = do.call(tm_polygons, c(list(...), list(options = options$polygons)))
 	tmp[[1]] = within(tmp[[1]], {
 		trans.fun = tmapTransCartogram
-		trans.args = get("trans.args", envir = parent.env(environment()))
+		trans.args = options$cartogram$trans.args
 		trans.aes = list(size = tmapScale(aes = "area",
 										  value = size,
 										  scale = size.scale,
@@ -33,8 +71,48 @@ tm_cartogram = function(size = 1,
 										  chart = size.chart,
 										  free = size.free))
 		tpar = tmapTpar(area = "__area")
-		trans.isglobal = TRUE
+		trans.isglobal = FALSE
 		plot.order = po
 	})
 	tmp
 }
+
+
+tm_cartogram_ncont = function(size = 1,
+							  size.scale = tm_scale(),
+							  size.legend = tm_legend_hide(),
+							  size.chart = tm_chart_none(),
+							  size.free = NA,
+							  plot.order = tm_plot_order("size", reverse = FALSE),
+							  options = opt_tm_cartogram_ncont(),
+							  ...) {
+	args = list(...)
+	do.call(tm_cartogram, c(list(size = size,
+								 size.scale = size.scale,
+								 size.legend = size.legend,
+								 size.chart = size.chart,
+								 size.free = size.free,
+								 plot.order = plot.order,
+								 options = options), args))
+}
+
+
+
+tm_cartogram_dorling = function(size = 1,
+								size.scale = tm_scale(),
+								size.legend = tm_legend_hide(),
+								size.chart = tm_chart_none(),
+								size.free = NA,
+								plot.order = tm_plot_order("size", reverse = FALSE),
+								options = opt_tm_cartogram_dorling(),
+								...) {
+	args = list(...)
+	do.call(tm_cartogram, c(list(size = size,
+								 size.scale = size.scale,
+								 size.legend = size.legend,
+								 size.chart = size.chart,
+								 size.free = size.free,
+								 plot.order = plot.order,
+								 options = options), args))
+}
+
diff --git a/R/tm_layers_text.R b/R/tm_layers_text.R
index 4852c500..55891cc2 100644
--- a/R/tm_layers_text.R
+++ b/R/tm_layers_text.R
@@ -493,7 +493,6 @@ tm_labels = function(text = tm_const(),
 					angle.legend = tm_legend_hide(),
 					angle.chart = tm_chart_none(),
 					angle.free = NA,
-					shadow = FALSE,
 					plot.order = tm_plot_order("AREA", reverse = FALSE, na.order = "bottom"),
 					zindex = NA,
 					group = NA,
diff --git a/R/tm_shape.R b/R/tm_shape.R
index 8c12d657..b4af1b53 100644
--- a/R/tm_shape.R
+++ b/R/tm_shape.R
@@ -30,6 +30,7 @@
 #' @importFrom rlang missing_arg expr
 #' @importFrom grDevices col2rgb colorRampPalette colors dev.off dev.size png rgb
 #' @import utils
+#' @example ./examples/tm_shape.R  
 #' @export
 tm_shape = function(shp, 
 					bbox = NULL,
diff --git a/R/tmapTrans.R b/R/tmapTrans.R
index 25c949b0..af2e57f3 100644
--- a/R/tmapTrans.R
+++ b/R/tmapTrans.R
@@ -248,15 +248,17 @@ tmapTransCartogram = function(shpTM, area, ord__, plot.order, args, scale) {
 	message("Cartogram in progress...")
 		
 	x = sf::st_sf(geometry = s, weight = area, tmapID__ = shpTM$tmapID)
+	x = x[x$weight > 0,]
 	
+
 	rlang::check_installed("cartogram")
 	
 	if (args$type == "cont") {
 		shp = suppressMessages(suppressWarnings({cartogram::cartogram_cont(x, weight = "weight", itermax = args$itermax)}))
 	} else if (args$type == "ncont") {
-		shp = suppressMessages(suppressWarnings({cartogram::cartogram_ncont(x, weight = "weight")}))
+		shp = suppressMessages(suppressWarnings({cartogram::cartogram_ncont(x, weight = "weight", k = args$expansion, inplace = args$inplace)}))
 	} else if (args$type == "dorling") {
-		shp = suppressMessages(suppressWarnings({cartogram::cartogram_dorling(x, weight = "weight")}))
+		shp = suppressMessages(suppressWarnings({cartogram::cartogram_dorling(x, weight = "weight", k = args$share, itermax = args$itermax)}))
 	} else {
 		stop("unknown cartogram type", call. = FALSE)
 	}
diff --git a/examples/tm_cartogram.R b/examples/tm_cartogram.R
new file mode 100644
index 00000000..2cea63d7
--- /dev/null
+++ b/examples/tm_cartogram.R
@@ -0,0 +1,23 @@
+Africa = World[World$continent == "Africa", ]
+
+#step3 L50: to do: trans.isglobal needs another variant trans.apply_from_here
+tm_shape(Africa, crs = "+proj=robin") + 
+	tm_cartogram(size = "pop_est", options = opt_tm_cartogram(itermax = 15)) +
+	tm_text("name")
+
+
+tm_shape(Africa, crs = "+proj=robin") + 
+	tm_cartogram_ncont(size = "pop_est", options = opt_tm_cartogram_ncont()) +
+	tm_text("name")
+
+tm_shape(World, crs = "+proj=robin") +
+	tm_polygons() +
+	tm_cartogram_ncont(size = "pop_est", fill = "yellow")
+
+
+# to do: make output like this:
+W = cartogram_ncont(World |> st_transform("+proj=robin"), weight = "pop_est")
+tm_shape(World, crs = "+proj=robin") +
+	tm_polygons() +
+tm_shape(W) +
+	tm_polygons(fill = "yellow")
diff --git a/examples/tm_shape.R b/examples/tm_shape.R
new file mode 100644
index 00000000..f7d071d6
--- /dev/null
+++ b/examples/tm_shape.R
@@ -0,0 +1,2 @@
+tm_shape(World, crs = "+proj=robin", filter = World$continent=="Africa") + 
+	tm_polygons()
\ No newline at end of file