In LabVIEW, you can add cursors to the Waveform Graph and track their values through the Cursor Legend. If you need programmatically access the coordinates of each cursor, you can do so by manipulating the properties of the graph and its cursors. The attached example program demonstrates how to access the cursor coordinates using property nodes, and then determine if the cursors' position has been moved. The VI uses the Property Node "Cursor List" to get the location from the graph and then parses the data into arrays using Index Array and the assigns that to a Unbundle By Name to get the Position. This general idea can be manipulated to make a more robust graph indicator.