Explorer Map

Explorer maps are special maps used to aid in finding rare generated structures.

Trading
Woodland and ocean explorer maps can be bought from cartographer villagers by unlocking their tier 4 trades. An ocean explorer map is sold for 12–20 emeralds and a compass, and a woodland explorer map is sold for 16–28 emeralds and a compass.

Locating structures
There are two (three) types of explorer maps: woodland, ocean, and buried treasure. The maps differ from a normal map, in that it shows the area's land-water outline, as well as an orange striated texture for areas below sea level, and the blank map texture for land above sea level. The maps show a section of land that contains a woodland mansion, ocean monument or buried treasure respectively. This may not be the nearest such structure to the player. The structures are displayed as a small icon. If the player icon is smaller than it would be on a normal map, that means the player is a great distance away. When the player is less than 1027 blocks away from the map border, the icon will return to the proper size. When the player reaches the map's area of land (512*512), the map will fill in like a normal map.

The basic functions of a buried treasure explorer map are similar to that of the other two. However, instead of showing the structure icon on the map, it shows a red X instead. The buried treasure structure is located on the same X and Z coordinates as the middle of the X. To locate the chest spot, hold the treasure map with both hands, not in the offhand slot.

Cloning
The parts of the world that have already been explored and mapped will be copied, and newly explored areas will appear on both instances. In Creative mode, cloned explorer maps can be obtained by pick blocking on the explorer map displayed on item frames (make sure the map is out of your inventory when using pick block, or else that map will just be moved into your active hotbar slot).

ID
Explorer maps use the item id of regular maps,  in Java Edition and   in Pocket Edition.

Item data
An explorer map differs from a map in that its  tag is set, which includes a   and a  ; also its   list includes an entry for its target monument, mansion, or buried treasure (ver. 1.13). Its map item entry is identical to that of a normal map, except that by the time the player sees it, its  byte array is pre-filled with explorer maps' characteristic land-water boundary lines and water shading.

It should be noted that this additional data is stored in the Cartographer's NBT data and in the inventory item's NBT data, and not in the map file (e.g. map_0.dat). If you were to use the /give command to give yourself a map with the same map ID as an existing explorer map, it will still have the Ocean Monument/Woodland Mansion icon on the map, but it will simply be named "Map" instead of, for example, "Ocean Explorer Map".
 * Item data
 * : How the map looks in an item slot. See also Player.dat_format.
 * : The name the map is given. In this case, they are localized strings: either,  or.
 * : Color codes are calculated from the Red, Green and Blue components using this formula:  Red <<16 + Green <<8 + Blue .  Monument maps use 3830373, which is . Mansion maps use 5393476, which is .  Buried treasure explorer maps do not use a color code.
 * : One of these for each icon on the map. Explorer maps always have at least one representing their target.
 * : An arbitrary unique string identifying the decoration. For explorer map target structures, this is "+".
 * : The rotation of the icon. For explorer map target structures, this is always 180.
 * : The ID of the map icon: 8 for a mansion map, 9 for a monument map, 26 for a treasure map.
 * : The world x-coordinate of the target structure icon.
 * : The world z-coordinate of the target structure icon.
 * : The world x-coordinate of the target structure icon.
 * : The world z-coordinate of the target structure icon.
 * Notes

In Bedrock Edition, the item Data Value distinguishes explorer maps from one another and from filled locator maps:

Trivia

 * When a cartographer generates the trade offers for the explorer maps, it chooses the location of one of the nearest structures of the respective type (ocean monument or woodland mansion) in a chunk that has not yet been generated. This means that it will always select a structure that no player has visited yet. This is especially useful in multiplayer for finding unraided ocean monuments in order to obtain sponge blocks.
 * For the reason above, explorer maps obtained from one cartographer will always be the same. Also, if two cartographers unlock the explorer map trades approximately at the same place and the same time, the map locations will usually be identical.
 * Explorer maps fill as the chunks are generated, rather than when the player holds them while in the area; leaving an explorer map while exploring the area will still fill the map.