Classic has changed. The zones that were torn apart with the release of Cataclysm (v4) were then re-organised in BfA (v8). Classic was released subsequently with old maps but new attributes meaning that neither the retail nor the old Classic data points for gathering were correct.
Thanks to data collected from the original Gathermate project (data points and format) as well as the doomed AVR (pre-Cata zone IDs) and some time we now have Neoclassical data...
Install this addon like any other (copy folder to the Addons folder or as I do, use Curse client)
- Start the game, go to the main (Esc) menu
- GatherMate 2
- Select what you want to import and whether to merge with your existing data or replace it
- Ignore the Expansion
- Click "Import GatherMate..."
- Once done you should see the nodes on your map (assuming you have GatherMate2 set to display them)