Wikipedia:Manual of Style/Diagrams and maps

The following are draft Wikipedia guidelines for the use of diagrams and maps in articles.

Diagrams (including charts) and maps are valuable additions to Wikipedia pages when they fulfil these criteria: Other qualities such as being entertaining, "eye-candy", startling or artistically rendered do not compensate for lacks in the above criteria. Avoid chartjunk.
 * They give an explicit presentation that is directly relevant to the subject of the article(s) in which they appear
 * They are fully consistent with, and support, the surrounding text
 * Their style and density of information are chosen to appeal to a general reader

Standards
Such images must adhere to Image use policy, like any other. In particular, do not violate copyright by using all or portions of a diagram or map published in another source. Instead create a new one, presenting the information germane to the Wikipedia article(s) the image is intended for.

For diagrams of chemical structures, see WikiProject Chemistry/Structure drawing for guidance. &#91;There are probably others that could be pointed to here.&#93;

For maps, where possible use the blank map images available at Blank maps when producing new maps. See also the WikiMedia Commons Project Mapmaking Standards and its talk page.

File formats and uploading
It is preferable that diagrams and maps be saved in the SVG file format. This is an open standard for vector image files. If saving the image as a raster graphic, the PNG file format is generally preferred, though JPEG is acceptable. Very simple animations can be saved in the GIF file format. Other formats are strongly deprecated.

Upload your finished image to WikiMedia Commons, giving the image an appropriate, descripive filename that can be understood at a glance. Categorize it appropriately (it may be helpful to look at the pages of other, similar diagram or map images in Commons to see how they are categorized).

Presentation
When possible, use tables rather than diagrams to present simple tabular data, and use mathematical markup to produce formulas.

Avoid making a diagram or map so dense that it reduces readability or comprehensibility. On the other hand, diagrams should avoid the inclusion of big areas of empty, non-informative space inside the image.

Maps should present necessary geographic details, not every possible detail. The level of detail on a map should be selected so as to make the map useful to experts familiar with the subject, and also to users who are not at all familiar with it. Some information that an expert may not deem necessary might be necessary to others. For example, those with a geographical knowledge of Europe may not need to have neighbouring countries marked on a map of France, although this feature could be useful to those unfamiliar with the continent.

Maps showing a small geographic area should also have an inset locator map, locating that small geographic area in the context of a larger area, such as a continent or island chain. For example, see this map.

Avoid blank space in the image around its main content to give the illusion of a margin around the image. Wikipedia's image displaying code already handles spacing of images in relation to text and other images. A thin black border may be desirable as an element of the image itself, however, especially if the image is predominantly white or near-white.

Fonts
The Wikimedia renderer only knows specific, free fonts, a list of which can be found here. Other, non-free fonts such as Arial, Verdana, Helvetica etc. are replaced by a similar one. The Noto fonts are a good choice to use since they provide visual consistency across a wide range of scripts and languages.

Labels
Diagrams and maps should not include the image title (e.g. "Map of Azerbaijan", "Timeline of Events", etc.) in the image itself. The title is given in the article with the image caption feature and in the image filename, so having the title inside the image is redundant.

In general, labels of items within the diagram or map should use headline style, in which most words are capitalized. To quote the Chicago Manual of Style, 14th Edition: "In regular title capitalization, also known as headline style, the first and last words and all nouns, pronouns, adjectives, verbs, adverbs, and subordinating conjunctions (if, because, as, that, etc.) are capitalized. Articles (a, an, the), coordinating conjunctions (and, but, or, for, nor), and prepositions, regardless of length, are lowercased unless they are the first or last word of the title..."

In maps, bodies of water such as rivers, lakes, and oceans should be labeled in italics. Many map makers use a dark blue for the font. ''&#91;More recommendations are needed. Should capital cities be bold? Regions in Small Caps ? What about use of letter and word spacing? Serif font? Etc.&#93;''

When inserting an image into an article, consider using the legend template to include a legend in the image caption.

Colors
When considering what colors to use in diagrams and maps, try to use colors that are subtle and pleasant rather than bold and garish. Also, try to avoid using colors in a way that would cause difficulty for those with color blindness or black-and-white monitors. Try viewing your image in greyscale to see if neighboring or overlapping colors could be indistinguishable to some.

Colors in maps
The following colors are recommended for use in creating basic maps.

References, projection and scale
Like articles, all maps and diagrams should include a complete set of references (see Verifiability). For maps, the image page should also include information on the map projection.

Except for the largest maps, maps should include a scale.