I do ROV mapping by shareware “OpenCPN”
I get nautical chart, ship and ROV plotted live on screen.
Easy to add waypoints etc to navigate ship as well as ROV at the same time.
Note the trix in the end of the post that you have to send ROV position as NMEA TLL; plotting systems only allow one “ship”
That software also makes a track of the ROV if you like.