Snapping (here we are making a vector layer of trail data)
Are you still with me? Ok, so snapping is a great way to georeference. So, you have your known and unknown data, right? Using the editing tool bar click the drop down to ‘start editing’note: you can only edit one data frame so if given the choice click on the one you want to edit. Using the same drop down set your ‘snapping,’ click on what you want to snap, in our case it is roads and trails. Now you want to use the edit tool to (Task) create a new feature in this case, and here we are tracing along the lines of the trails- The goal here is to make a vector layer of trail data. You can double click when you're finished and the feature will highlight. Then you can go into the attribute table and add data.
Trace tool Will allow you to trace along a feature that is highlighted, exactly copying it
How to highlight a feature click on it with your edit tool