Last night I added the following features:

• Enter in x/y/z Co-ordinates
• Draw lines between each x/y located on the same z

I also added 2 additional bits:

• Enter in Tag/x/y/z/Code (change)
• Draw Label with text Code

I will also look into adding the ability to drag the Labels around, thus allowing the user to have control over them.

To do:

• Specify how smooth line edges are to be drawn
• Save to local editable format
• Export to AutoCAD (*.dxf) format
• Drag Labels to new position

I also need to add some math for the line draw function, as at the moment it just draws all lines on the same Z by going through the list in order, rather than determining which is the nearest co-ordinate.