fix geotiff multi-channel plotting in gui

pyglance/glance/gui_figuremanager.py

@@ -467,7 +467,7 @@ class GlanceGUIFigures (object) :
             if dataForm == SIMPLE_2D :
 
                 # double check that our data is a shape we can handle for this type of plot
-                if len(data_object_to_use.data.shape) != 2 :
+                if not plotAsRGB and len(data_object_to_use.data.shape) != 2 :
                     raise ValueError("Two dimensional data is required for this plot type. "
                                      "The provided variable data is "
                                      + str(data_object_to_use.data.shape) + " shaped.")