I like all of this and support it. I think the maps work on a grid because it is easier to map adjacent maps that way. If it always centered on where the player made a map, you would need to make sure you travel the EXACT perfect distance to make your next map or there would be overlap between the two maps on their connecting edge. I'm think it also has something to do with how map data is stored but not sure.
You would need a way to make new adjacent maps snap perfectly to the existing map to fix the overlap problem. Maybe if you put your existing map in the center of a 3x3 crafting grid and a blank map of the same zoom level in one of the surrounding slots, it will set that map's origin point to whatever is the correct location so they line up right?
Since the cartography table will now handle the cloning of maps, that seems the most functional.
Thanks for the support. The feature has been added.
Would the waypoints just be applied at player/table location, or could you define the location yourself? Currently, you have to place the banner inworld to make the waypoint (if you didn't already know, this is a thing now). It doesn't really make much sense to redo this in a way that still requires you to go there. If the banner were renamed to have a specific pattern format, we could supply the coordinates that way (unnamed banners would assume player/table location)
Perhaps a new UI item could be added to the table that lets you define extra info according to what the current "plus" item is? This could perhaps take advantage of the accessibility features recently added in 19w11a. For example, the shears could allow you to specify the zoom level to jump to allowing you to crop down more than one level at a time (probably 1 durability per level changed?). Paper or empty maps could be used similarly to zoom outwards (again, one item per level moved). An unnamed banner could allow you to specify the waypoint coordinates, leaving it blank would default to current location. And a compass (not consumed, but perhaps a durability would be added to the item that decrements by 1 for each change) could allow you to cycle through multiple waypoints.
The suggested changes would actually make setting waypoints easier as you can just add it via cartography table to a location far away from you. I do not understand your coordinates suggestion. Durability for compasses sounds like a good idea considering the power of the suggested ability. However, I will need to add more uses to the compass.