Minecraft wiki entry for Map, associated text:  map: The map number.
 map_scale_direction: Only internally used when scaling a map, after that directly removed: The amount to increase the current map scale by when crafting. Always 1.
 map_to_lock: 1 or 0 (true/false) - true if the map should be locked after being taken out of the cartography table. Only internally used when locking a map, after that directly removed.
 Decorations: A list of optional icons to display on the map. Decorations that are removed or modified do not update until the world is reloaded.
An individual decoration.
 id: An arbitrary unique string identifying the decoration.
 type: The ID of the map icon to display.
 x: The world X position of the decoration.
 z: The world Z position of the decoration.
 rot: The rotation of the symbol, ranging from 0.0 to 360.0, measured clockwise. A rotation of 0 displays the icon upside-down compared to its appearance in the icon texture.
 display: The display tag.
 MapColor: The color of the markings on the item's texture.