The method that is used to locate items is simply a catalog/database of significant screen shots. Each mountain has a unique profile which is associated with its number in the above Reference numbers map. Significant screen shots are simply those screen shots that provide a clear view of a mountain's profile. Establishing the catalog/database of mountain profiles is time consuming, but necessary in locating items.
The location of items are usually identified by the position of surrounding known mountain profiles, although there are occasionally (very rare) background errors that have to be resolved.
Unknown locations can then be identified by comparing significant items in unknown locations against known cataloged screens shots.
In addition to the method used above: Logic, time, dialog, direction, maps, map markings, satellite phone maps, wall paintings of the island, Island photographs, distances, etc., are also used in trying to locate an item.
Locations can't be identified through subjective manners or because they 'feel right'. An accurate map must use an unbiased, objective method to locate items.
The accuracy of the map should increase as the show progresses as more material used to develop the map becomes available.