Ternary Plot and Heatmap

[mags612]

1. Ternay plot shows up after double clicking the triangular icon, but also get the following error:
   Traceback (most recent call last):
   File "/Users/maggie/Desktop/LaME/LaserMapExplorer/main.py", line 4964, in plot_ternarymap
   self.style.set_style_widgets('ternary map')
   File "/Users/maggie/Desktop/LaME/LaserMapExplorer/src/app/StyleToolbox.py", line 1639, in set_style_widgets
   parent.update_field_type_combobox(parent.comboBoxColorByField,addNone=True,plot_type=plot_type)
   File "/Users/maggie/Desktop/LaME/LaserMapExplorer/main.py", line 2868, in update_field_type_combobox
   field_list.insert(0, 'None')
   ^^^^^^^^^^
   UnboundLocalError: cannot access local variable 'field_list' where it is not associated with a value

2. Heatmap plot does not work (either with two or three elements), no error message.