Hello Martin,
I've made 2 additional nodes (some bugs at the moment) CSV-File reader that evaluates points. You can select the columns individually in the node. The node can also read only numbers -> output a numarray. A second node idxReplace replaces values in a numarray by the index.

Here is a first result:



I will try to find the bugs in the next days and post an update of the node editor.

Have a nice day
Karsten