diff --git a/items.lua b/items.lua
index 18d7fd5..c23cfb3 100644
--- a/items.lua
+++ b/items.lua
@@ -202,9 +202,20 @@ end
 --
 -- Returns the id of the new map
 local function map_from_meta(meta, player_x, player_z)
-    local size = meta:get_int("cartographer:size") or 10;
-    local detail = meta:get_int("cartographer:detail") or 1;
-    local scale = meta:get_int("cartographer:scale") or 1;
+    local size = meta:get_int("cartographer:size");
+    if size == 0 then
+        size = 40;
+    end
+
+    local detail = meta:get_int("cartographer:detail");
+    if detail == 0 then
+        detail = 1;
+    end
+
+    local scale = meta:get_int("cartographer:scale");
+    if scale == 0 then
+        scale = 1;
+    end
 
     local total_size = size * scale;