This data pack cannot be used on versions earlier than 1.15, as the game does not support predicates then.

Beware, due to the very nature of explorer maps, your game may freeze, albeit very slightly, upon the spawning of a wandering trader who has a map for sale or when a compass is converted in the nether. This freezing is unavoidable, since the game has to generate the landscape and structure in order to make a map. Even on my slow computer, the freezing only lasts a few seconds and no more. This is just a warning that one should heed.

A small known "half-bug" is that, sometimes, maps and compasses may overlap in destination with previous purchases. In other words, one map bought at one time and another bought at a different time may both lead to the same place, resulting in wasted emeralds. This is due to the generation of explorer maps. If users bought a map/compass, but refrain from exploring the destination, the destination will not be considered explored. Thus, maps and compasses would still point to the closest unexplored area. This is not really a bug, but more so a feature of explorer maps. I cannot resolve this half-issue, anyways. Just avoid stockpiling maps and compasses and actually use them to explore.

There is also a very rare bug. Sometimes, if users buy a map, it may result in a blank, unusable map. This happens when no destination structure is found at all, such as when the user has used world generation settings like single biome worlds, which prevent certain structures from spawning at all. This is not an issue that I can resolve.

To uninstall, please run the command /function bm_travelermaps:uninstall.

This data pack prepends a map to the beginning of the list of trades of the wandering trader. Thus, it is compatible with all other data packs that change the trader's base trades, appends, or prepends other trades to the trade list. Remember to load this data pack AFTER any data packs that change the trader's trades, rather than append/prepend trades.

However, it is not compatible by default with Regional Wandering Traders Data Pack, as their code structure overwrites the trader's trades multiple times before stopping.

For the versions that are compatible with the Regional Wandering Traders Data Pack, please load this data pack after Regional Wandering Traders. Do not load any other data packs that append nor prepend any new trades to the wandering trader before this data pack. You must load those after this data pack. The creation of explorer maps is very intensive and complicated, so this data pack needs to reserve a specific spot in the trader's trade data in order to copy the map data there. Loading other data packs that append or prepend trades before this data pack would disrupt the copying.

When a wandering trader is eligible to sell maps, there is a 75% chance of the loot being a map, with the probabilities for each structure listed in the list above. A map is generated and copied into the trader's list of trades. This always causes the game to freeze, due to the how explorer maps are generated and cannot be changed. The remaining 25% is a chance for loot to be a Mysterious Compass, which would lead users to a nearby ruined portal. An explorer map is generated for a ruined portal, then copied into the compass data, allowing the lodestone compass to be usable. Once in the nether at any time, the Mysterious Compass will shake and fizzle (with your imagination), converting into either a Wither or Piglin Compass, leading users to either a fortress or a bastion remnant. Both are equally likely.

Compasses still use explorer map generation to generate the destination coordinates, thus causing freezing. I tried various experimental methods of triangulation with commands, which does not cause the freezing of explorer maps and is extremely fast to calculate. However, Minecraft's scoreboard has limited precision. This causes the triangulation to become inaccurate for destinations at either very long distance away (>1500 blocks) or at very short range (<20 blocks). I tried my hardest to implement a non-freezing algorithm to lead users to nether structures, but the limited precision of the in-game mathematical commands is the main reason why faster, more user-friendly structure-finding algorithms were scrapped. I am sorry that this data pack has to rely on the slow explorer map generation in the end. Minecraft's commands are inefficient and limited.

The optimised version uses a hidden advancement which triggers the functions to enable the wandering trader to sell maps upon the player interacting with it. However, due to the limitation of minecraft advancements, the functions trigger one tick after when the advancement is awarded. Thus, the game would show players the trader's old trades without the option to trade the map visible. However, the trader is able to sell the map, but the opened menu would be outdated. Thus, players using the optimised version must interact with the trader a second time to see the trade.

The data pack reserves the very first trading slot as the location to which to copy the map data. However, Regional Wandering Traders overwrites that slot multiple times before stopping. For compatibility, instead of copying the map data to the first trading slot, the functions instead copies the map data to the 7th slot to avoid overwriting.