Module:Location map/data/USA Alaska/doc

Template:Location map USA Alaska is a location map definition used to overlay markers and labels on a map of Alaska. It is used by "Template:Location map" when invoked with parameter "USA Alaska": {{Location map | USA Alaska | ...}}. The markers are placed by latitude and longitude coordinates on the default map or a similar map image.

[[Image:Template:Location map/data/USA Alaska|left|thumb|200px|Location map for Template:Location map/data/USA Alaska]]

Map parameters
name	Template:Location map/data/USA Alaska	name used in default map caption
image	Template:Location map/data/USA Alaska	file name of map image, without "Image:" or "File:"
x	Template:Location map/data/USA Alaska	an expression which returns 0 for the left edge of the map, and 100 for the right edge of the map, where {{{2}}} and {{{3}}} are the degrees latitude and longitude respectively.
y	Template:Location map/data/USA Alaska	an expression which returns 0 for the top edge of the map, and 100 for the bottom edge of the map, where {{{2}}} and {{{3}}} are the degrees latitude and longitude respectively.

Usage

For a description of the parameters, see {{Location map}} and {{Location map many}}.

Location map: Eastern hemisphere, Deg/Min/Sec coordinates

Attu Island

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Location of Attu Island in Alaska

{{Location map | USA Alaska
| width = 200
| float = right
| label = Attu Island
| position = right
| caption = Location of [[Attu Island]] in Alaska
| lat_deg =  52 | lat_min= 54 | lat_sec = 09 | lat_dir = N
| lon_deg = 172 | lon_min= 54 | lon_sec = 34 | lon_dir = E
}}

Location map: Eastern hemisphere, Decimal coordinates

Attu Island

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Location of Attu Island in Alaska

{{Location map | USA Alaska
| width = 200
| float = right
| label = Attu Island
| position = right
| caption = Location of [[Attu Island]] in Alaska
| lat = 52.9025
| long = 172.909444
}}

Location map: Western hemisphere, Deg/Min/Sec coordinates

Ketchikan

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Location of Ketchikan in Alaska

{{Location map | USA Alaska
| width = 200
| float = right
| label = Ketchikan
| position = left
| caption = Location of [[Ketchikan]] in Alaska
| lat_deg =  55 | lat_min= 21 | lat_sec = 00 | lat_dir = N
| lon_deg = 131 | lon_min= 40 | lon_sec = 24 | lon_dir = W
}}

Location map: Western hemisphere, Decimal coordinates

Ketchikan

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Location of Ketchikan in Alaska

{{Location map | USA Alaska
| width = 200
| float = right
| label = Ketchikan
| position = left
| caption = Location of [[Ketchikan]] in Alaska
| lat = 55.35
| long = -131.673333
}}

Location map many: Deg/Min/Sec coordinates

Attu Island

Ketchikan

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Attu Island and Ketchikan in Alaska

{{Location map many | USA Alaska
| float = right | width = 200
| caption = [[Attu Island]] and [[Ketchikan]] in Alaska
| label = Attu Island | label_size = 90 | pos = right
| lat_deg =  52 | lat_min= 54 | lat_sec = 09 | lat_dir = N
| lon_deg = 172 | lon_min= 54 | lon_sec = 34 | lon_dir = E
| label2 = Ketchikan | label2_size = 90 | pos2 = left
| lat2_deg =  55 | lat2_min= 21 | lat2_sec = 00 | lat2_dir = N
| lon2_deg = 131 | lon2_min= 40 | lon2_sec = 24 | lon2_dir = W
}}

Location map many: Decimal coordinates

Attu Island

Ketchikan

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Attu Island and Ketchikan in Alaska

{{Location map many | USA Alaska
| float = right | width = 200
| caption = [[Attu Island]] and [[Ketchikan]] in Alaska
| label = Attu Island | label_size = 90 | pos = right
| lat = 52.9025
| long = 172.909444
| label2 = Ketchikan | label2_size = 90 | pos2 = left
| lat2 = 55.35
| long2 = -131.673333
}}

Technical details

For a map using an equirectangular projection which does not cross +/-180 longitude, or +/-90 latitude, the following expressions can be used:

x = 100*(long - left)/(right - left)
y = 100*(lat - top)/(bottom - top)

where lat and long are the degrees latitude and longitude respectively. Here, top and bottom are the degrees latitude of the top and bottom edges of the map, left and right are the degrees latitude of the left and right edges of the map.

Things are a bit more complicated when the map crosses +/-180 longitude, and some sort of "modulo arithmetic" is required. Here, we add 360 if the longitude is less than 0, then use a mapping based on positive coordinates. The following table can be used to check if the expressions are working as desired:

location	lat	long	(x,y) test	(x,y) exact
top/left	72	172	(,)	(0,0)
top/right	72	-129	(,)	(100,0)
bottom/left	51	172	(,)	(0,100)
bottom/right	51	-129	(,)	(100,100)
center	61.5	201.5	(,)	(50,50)