Template:Location map/Creating a new map definition

This help page is a how-to guide. It explains concepts or processes used by the Wikipedia community. It is not one of Wikipedia's policies or guidelines, and may reflect varying levels of consensus.

This guides explains how to create map definitions for the {{Location map}} family of templates.

This section needs expansion. You can help by adding to it. (August 2011)

The templates utilize any one of a set of map definitions. These are not forks but rather auxiliary pages and must have names following the pattern "Module:Location map/data/location" or "Template:Location map location", where location is the name of the area covered by the map. The template space is supported only for backward compatibility; all new map definitions should be created as modules. Important: If a new map has the same projection and boundaries as the old map (such as File:Iraq location map.svg and File:Iraq location map2.svg), a new definition should not be created; instead, the old definition should be used with the AlternativeMap parameter. To create a simple map definition module using an image of a map with an equirectangular projection having the equator as its standard parallel (aka plate carrée, “unprojected”, lat/lon projection):

1. Create a new map image and upload it to Wikimedia commons or find an existing map on the same site.
2. Create a module named Module:Location map/data/location, copy the content below into it and substitute the appropriate values.
3. Create a page named Module:Location map/data/location/doc and follow the instructions under #Documentation.

As an example of a map that uses an equirectangular projection, we use Module:Location map/data/Belgium. Please do not experiment using active templates.

return {
	name = 'Belgium',
	top = 51.8,
	bottom = 49.2,
	left = 2.2,
	right = 6.9,
	image = 'Belgium location map.svg',
	image1 = 'Belgium relief location map.jpg'
}

Maps of this type will work for small to mid sized areas. Module:Location map/data/USA Alabama is another example of a map description that uses an equirectangular projection. Notice that the image of the country is not what most would expect.

Maps that use other projections, such as Module:Location map/data/USA, which uses an equidistant conic projection. require formulas which are used to calculate the x and y coordinates for the location mark. Understanding these formulas requires a familiarity with the subject, so you are more than welcome to skip this section.

The input $1 is the latitude and $2 is the longitude, both in decimal form. The expression follows the syntax of ParserFunction "#expr". The two output coordinates are defined such that the formula for x evaluates to 0 for the left edge of the image and 100 for the right edge; the formula for y evaluates to 0 for the top edge and 100 for the bottom edge.

It is easiest to use the de facto template at Template:Location map data documentation to generate the documentation page. Here is another example of what the documentation might look like:

<!-- Categories and interwikis go at the bottom of this page. -->
{{Location map data documentation|image=[[File:Belgium-CIA WFB Map.png|thumb|250px|Map of Belgium]]
|examples=
=== Location map, using default map (image) ===
{{Location map | Belgium
| width   = 200
| lat_deg = 50.85
| lon_deg = 4.35
| label   = Brussels
}}
<pre style="width:30em">
{{Location map | Belgium
| width   = 200
| lat_deg = 50.85
| lon_deg = 4.35
| label   = Brussels
}}
</pre>
{{clear}}

=== Location map many, using relief map (image1) ===
{{Location map many | Belgium
| relief   = yes
| width    = 200
| caption  = Two locations in Belgium
| lat1_deg = 50.85
| lon1_deg = 4.35
| label1   = Brussels
| lat2_deg = 51.22
| lon2_deg = 4.40
| label2   = Antwerp
}}
<pre style="width:30em">
{{Location map many | Belgium
| relief   = yes
| width    = 200
| caption  = Two locations in Belgium
| lat1_deg = 50.85
| lon1_deg = 4.35
| label1   = Brussels
| lat2_deg = 51.22
| lon2_deg = 4.40
| label2   = Antwerp
}}
</pre>
{{clear}}

=== Location map+, using AlternativeMap ===
{{Location map+ | Belgium
| AlternativeMap = Belgium relief location map.jpg
| width   = 200
| caption = Two locations in Belgium
| places  =
  {{Location map~ | Belgium
  | lat_deg = 50.85
  | lon_deg = 4.35
  | label   = Brussels
  }}
  {{Location map~ | Belgium
  | lat_deg = 51.22
  | lon_deg = 4.40
  | label   = Antwerp
  }}
}}
<pre style="width:35em">
{{Location map+ | Belgium
| AlternativeMap = Belgium relief location map.jpg
| width   = 200
| caption = Two locations in Belgium
| places  =
  {{Location map~ | Belgium
  | lat_deg = 50.85
  | lon_deg = 4.35
  | label   = Brussels
  }}
  {{Location map~ | Belgium
  | lat_deg = 51.22
  | lon_deg = 4.40
  | label   = Antwerp
  }}
}}
</pre>
}}
<includeonly>
<!-- Categories go here, and interwikis go on Wikidata: -->

[[Category:Belgium location map templates|Belgium location map templates]]

</includeonly>