{{Nutshell|[[Map|Maps]]s and [[Lineline chart|line charts]]s used as illustrations followare theequally samesubject rulesto asthe picturesguidelines that are used asfor illustrations.|Maps and line charts may be used as sources,butare equally subject to the core content policies of [[WP:V|Verifiabilityverifiability]], and [[WP:NOROR|Nono original research]] still apply.|It is not [[WP:OR|original research]] to extract information from a map or line chart using standard techniques, particularly if those techniquesemployed areacross common to two or moremultiple disciplines.|The core content policies of [[WP:V|Verifiability]], and [[WP:NOR|No original research]] apply to user-made maps.}}
[[File:1930 D&RGW WP.jpg|thumb|300pxupright=1.35|This map is a commercial map of the [[Denver and Rio Grande Western]] and [[Western Pacific Railroad]]s as they existed in 1914. This map is valuable as a source of information and as illustration for what it depicts. The map depicts the general route of the two railroads advertised, the route of their primary rivals, several long abandoned [[short line railroad]]s and short-lived mining [[boomtown]]s in the [[western United States]], and this map is used appropriately in articles about these subjects. However, the map's limitations should also be understood. Comparing this map with others will reveal that this commercial map is drawn on an inconsistent scale, perhaps to minimize the fact that the competing [[Overland Route (Union Pacific Railroad)|Overland Route]] is more direct than the route of the railroads advertised.]]
Any map or line chart used in Wikipedia should conform with Wikipedia's policies of [[WP:neutrality|neutrality]], [[WP:reliabilityverifiability|reliabilityverifiability]], and [[WP:verifiabilityNOR|verifiabilityno original research]]. Maps can be used for two purposes in Wikipedia articles, as sources or as illustration. Regardless of the point of using a map in an article, the following points should be kept in mind:
*The presence of an object on a map is not sufficient by itself to show [[WP:notability|notability]] of a subject.
*Even maps produced using reliable sources (such as [[GIS]] data) can have minor errors as a result of errors in the underlying database, or the cartographer trying to overlay data from two non-linear sources. Minor map errors are common, for that reason any map detail that is key to the article should be confirmed with a separate map from a different publisher. Rarely are map errors notable, even if they have gone uncorrected for decades.
