Minecraft wiki entry for Item_modifier, associated text: exploration_map—Converts an empty map into an explorer map leading to a nearby generated structure.
 destination: The type of generated structure to locate. Accepts any of the StructureTypes used by the /locate command (case insensitive).
 decoration: The icon used to mark the destination on the map. Accepts any of the map icon text IDs (case insensitive). If mansion or monument is used, the color of the lines on the item texture changes to match the corresponding explorer map.
 zoom: The zoom level of the resulting map. Defaults to 2.
 search_radius: The size, in chunks, of the area to search for structures. The area checked is square, not circular. Radius 0 causes only the current chunk to be searched, radius 1 causes the current chunk and eight adjacent chunks to be searched, and so on. Defaults to 50.
 skip_existing_chunks: Don't search in chunks that have already been generated. Defaults to true.