Handled automatic collation of DynamicMaps

holoviews/plotting/renderer.py

@@ -18,7 +18,7 @@
 from .. import DynamicMap
 from . import Plot
 from .comms import JupyterComm
-from .util import displayable, collate
+from .util import displayable, collate, initialize_dynamic
 
 from param.parameterized import bothmethod
 
@@ -159,16 +159,12 @@ def get_plot(self_or_cls, obj, renderer=None):
         """
         Given a HoloViews Viewable return a corresponding plot instance.
         """
+        # Initialize DynamicMaps with first data item
+        initialize_dynamic(obj)
+
         if not isinstance(obj, Plot) and not displayable(obj):
             obj = collate(obj)
-
-        # Initialize DynamicMaps with first data item
-        dmaps = obj.traverse(lambda x: x, specs=[DynamicMap])
-        for dmap in dmaps:
-            if dmap.sampled:
-                # Skip initialization until plotting code
-                continue
-            dmap[dmap._initial_key()]
+            initialize_dynamic(obj)
 
         if not renderer: renderer = self_or_cls.instance()
         if not isinstance(obj, Plot):

holoviews/plotting/util.py

@@ -43,12 +43,12 @@ def collate(obj):
                                 "(http://git.io/vtIQh)" % nested_type)
         return obj.collate()
     if isinstance(obj, HoloMap):
-        display_warning.warning("Nesting %ss within a HoloMap makes it difficult "
+        display_warning.warning("Nesting {0}s within a {1} makes it difficult "
                                 "to access your data or control how it appears; "
-                                "we recommend calling .collate() on the HoloMap "
+                                "we recommend calling .collate() on the {1} "
                                 "in order to follow the recommended nesting "
                                 "structure shown in the Composing Data tutorial"
-                                "(http://git.io/vtIQh)" % obj.type.__name__)
+                                "(http://git.io/vtIQh)".format(obj.type.__name__, type(obj).__name__))
         return obj.collate()
     elif isinstance(obj, (Layout, NdLayout)):
         try:
@@ -70,6 +70,19 @@ def collate(obj):
         raise Exception(undisplayable_info(obj))
 
 
+def initialize_dynamic(obj):
+    """
+    Initializes all DynamicMap objects contained by the object
+    """
+    dmaps = obj.traverse(lambda x: x, specs=[DynamicMap])
+    for dmap in dmaps:
+        if dmap.sampled:
+            # Skip initialization until plotting code
+            continue
+        if not len(dmap):
+            dmap[dmap._initial_key()]
+
+
 def undisplayable_info(obj, html=False):
     "Generate helpful message regarding an undisplayable object"