Try the LineBuilder - This should do what you want. The lines will need to be ordered correctly though

"Connects input point features in the order they enter, forming linear or polygonal features." you'll need to group by your contour elevation.

The will probably create some issues when you have contours of the same elevation which should not be connected. That's another can of worms though.

Hi @virtualcitymatt​ thanks for your reply! Well the lines needing the breaks to be joined are actually just one feature... As in a feature is one line with a series of breaks in it which need filling.

I have used LineCombiner to effectively split these into separate features, but unsure where to go with that.

What about the Snapper did not work? I'd make sure to use the following settings:

Also very important to remember that the snapping distance is relative to the coordinate system of the input. Meaning that if the the incoming data is in degrees, the snapping distance must also be specified in degrees.

Ahhh interesting, the you can create an ID for each group of lines, use a Deaggregator to split them and then use the LineBuilder to connect them together (you can then group by the ID). You don't need the LineCombiner here. Again, this assumes that all line segments are ordered correctly.

The Snapper had a bad habit of forming undesired loops. A potential improvement could be had there

Ah ok great this works perfectly for some of them. But others it doesn't as the lines when deaggregated are not in order. An example of one not being in order here

Thanks @david_r​, as @virtualcitymatt​ says, often it created these loops in the polyline - even with the settings you suggest

You could try extracting the dangle nodes (nodes with only one connection) then using a neighbour finder, find which dangle nodes need to be connected and use the result to fill in the gap(s).

It won't improve the vertex order, but it should help get you a (visually) continuous line.

Thanks @hkingsbury​ - do you have a way you would do this?

Here's an example, its pretty rough and can be refined a bit, but should give you the general gist of it