[comment {-*- tcl -*- doctools manpage}]
[manpage_begin map::slippy n 0.2]
[moddesc   {Mapping utilities}]
[titledesc {Common code for slippy based map packages}]
[require Tcl 8.4]
[require Tk 8.4]
[require map::slippy [opt 0.2]]
[description]

This package provides a number of methods doing things needed by all
types of slippy-based map packages.

[section API]

[list_begin definitions]

[call [cmd ::map::slippy] [method length] [arg level]]

This method returns the width/height of a slippy-based map at the
specified zoom [arg level], in pixels. This is, in essence, the result
of

[example {
	expr { [tiles $level] * [tile size] }
}]


[call [cmd ::map::slippy] [method tiles] [arg level]]

This method returns the width/height of a slippy-based map at the
specified zoom [arg level], in [term tiles].


[call [cmd ::map::slippy] [method {tile size}]]

This method returns the width/height of a tile in a slippy-based map,
in pixels.


[call [cmd ::map::slippy] [method {tile valid}] [arg tile] \
	[arg levels] [opt [arg msgvar]]]

This method checks whether [arg tile] described a valid tile in a
slippy-based map containing that many zoom [arg levels]. The result is
a boolean value, [const true] if the tile is valid, and [const false]
otherwise. For the latter a message is left in the variable named by
[arg msgvar], should it be specified.

[para]

A tile identifier as stored in [arg tile] is a list containing zoom
level, tile row, and tile column, in this order. The command
essentially checks this, i.e. the syntax, that the zoom level is
between 0 and "[arg levels]-1", and that the row/col information is
within the boundaries for the zoom level, i.e. 0 ...
"[lb]tiles $zoom[rb]-1".


[call [cmd ::map::slippy] [method {geo 2tile}] [arg geo]]

Converts a geographical location at a zoom level ([arg geo], a list
containing zoom level, latitude, and longitude, in this order) to a
tile identifier (list containing zoom level, row, and column) at that
level.


[call [cmd ::map::slippy] [method {geo 2point}] [arg geo]]

Converts a geographical location at a zoom level ([arg geo], a list
containing zoom level, latitude, and longitude, in this order) to a
pixel position (list containing zoom level, y, and x) at that level.


[call [cmd ::map::slippy] [method {tile 2geo}] [arg tile]]

Converts a tile identifier at a zoom level ([arg tile], list
containing zoom level, row, and column) to a geographical location
(list containing zoom level, latitude, and longitude, in this order)
at that level.


[call [cmd ::map::slippy] [method {tile 2point}] [arg tile]]

Converts a tile identifier at a zoom level ([arg tile], a list
containing zoom level, row, and column, in this order) to a pixel
position (list containing zoom level, y, and x) at that level.


[call [cmd ::map::slippy] [method {point 2geo}] [arg point]]

Converts a pixel position at a zoom level ([arg point], list
containing zoom level, y, and x) to a geographical location (list
containing zoom level, latitude, and longitude, in this order) at that
level.


[call [cmd ::map::slippy] [method {point 2tile}] [arg point]]

Converts a pixel position at a zoom level ([arg point], a list
containing zoom level, y, and x, in this order) to a tile identifier
(list containing zoom level, row, and column) at that level.

[list_end]


[section References]

[list_begin enum]
[enum]	[uri http://wiki.openstreetmap.org/wiki/Main_Page]
[list_end]


[keywords slippy map location geodesy geography latitute longitude zoom]
[manpage_end]