Template:Location map/Creating a new map definition

Understanding map definition templates

The {{Location map}} family of 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. To create a simple map definition module using an image of a map with an equirectangular Mercator 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.

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'
}

Parameter	Description
name	The name of the area covered
top	The latitude of the top edge of the image using decimal degrees
bottom	The latitude of the bottom edge of the image
left	longitude of the left edges of the image
right	longitude of the right edges of the image
image	The name of the image file on Commons
image1	The name of an alternate image, usually a relief map, which can be accessed using the relief parameter.

Maps of this type work will 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 and is currently beyond the scope of this discussion. Note that the formula for x evaluates to 0 for the left edge of the image and 100 for the right edge. Likewise, the formula for y evaluates to 0 for the top edge and 100 for the bottom edge.