Tiles.CF

libtiles.tcl - Tiles Common Framework -
a micro-framework implementing common procedures
    for geo-tile processing. An extension of slippy
    map library.

 References and credits:
(1) https://wiki.tcl.tk/
    (2) https://msdn.microsoft.com/en-us/library/bb259689.aspx
    (3) http://wiki.openstreetmap.org/wiki/Slippy_map_tilenames
    (4) http://wiki.openstreetmap.org/wiki/Zoom_levels
    (5) https://en.wikipedia.org/wiki/Well-known_text
    (6) https://en.wikipedia.org/wiki/GeoJSON
    (7) http://docs.activestate.com/activetcl/8.6/tcllib/math/math_geometry.html

 Bugs:
    it looks that the current implementation of
    the slippy map library does not take into account 
    sign of lat/lon (all coordinates are positive only).
    It is fixed by functions tile2geo
getEpsilon 0 70 21
 tile2quadkey --
Convert tile coordinate (z/x/y) to quadkey. See (2) for details.

 Arguments:
        col    x tile coordinate,
        row    y tile coordinate,
        zl     zoom level.
 Results:
        quadkey
quadkey2tile --

Convert quadkey to tile coordinates (z/x/y). See (2) for details.

 Arguments:
        qkey    quadkey of tile
 Results:
        "x y zl" returns tile coordinate
tile2geo --

Convert tile coordinates (z/x/y) to lat/long. See (2) for details.
        Refinement of {::map::slippy tile 2geo} function. Order of input
        and output has been changes. 

 Arguments:
        col    x tile coordinate,
        row    y tile coordinate,
        zl     zoom level.
 Results:
        "x y" lat/long coordinates.
 See Bugs above.
trying to resolve a bug.
geo2tile --

Convert tile lat/long coordinates to tile coordinates.
        See (2) for details. Refinement of {::map::slippy geo 2tile} function.
        Order of input and output has been changes.

 Arguments:
        x     longitude,
        y     latitude,
        zl    zoom level.
 Results:
        "col row" col and row tile coordinates.
 See Bugs above.
getPixelSize --

Get tiles' pixel width in meters.

 Arguments:
        y     latitude,
        zl    zoom level.
 Results:
        width (or height) in meters.
 getEpsilon  --
Get tiles' pixel width in meters.

 Arguments:
        x     longitude,
        y     latitude,
        zl    zoom level.
 Results:
        width (or height) in meters.
 See (4).  
tile2geom --

 Arguments:
        col    x tile coordinate,
        row    y tile coordinate,
        zl     zoom level,
        type   (optional, default 0):
                 0 - EXTENT   - extent "Xmin Ymin Xmax Ymax",
                 1 - Tcl LIST - tcl polygon and central point (first and last points are same)
                     {{Xcent Ycent} {x1 y1 x2 y2 x3 y3 x4 y4 x1 y1}},
                 2 - WKT LIST - Tcl list of WKT data (See (5)) - first element is central
                     point, second element is polygon (first and last poins are same),
                 3 - GEOJSON LIST  - GeoJSON data list (first  is central point, second is polygon).
 Results:
        "x y" lat/long coordinates.
 isIn  --
Checks if any tile of one tile list is inside of
        any tileanother tiles list.
        Order of tile lists is not taken into account.

 Arguments:
        list_a     list of tile quadkeys,
        list_b     list of tile quadkeys,
        order      (optional,bool, default False) if order
                   in important. True
                   means that right need to be inside
                   or equal left.
 Results:
        0 - false, 1 - true. If a and b equal retuns true.
 isTouch  --
Checks if any tile of one tile list touches
        any tileanother tiles list.

 Arguments:
        list_a     list of tile quadkeys,
        list_b     list of tile quadkeys,
 Results:
        0 - false, 1 - true. If a and b equal returns true.
 polygonTileIntersect  --
cheks if a polygon and a tile are intersected

 Arguments:
        pol         - Tcl polygon (see (7)),
        col row zl  - tile coordinates
 Results:
        boolean
 getTilesOfPolygon  --
returns list of tiles of the intersecting a polygon.

 Arguments:
        pol     - Tcl polygon (see (7)),
        from_zl - from zoom level,
        to_zl   - (optional) if set, all tiles between defined
                  zoom levels will be returned. It has to be
                  bigger than from_zl.
 Results:
        list of tiles
 For testing/debugging:
--> https://t1.ssl.ak.dynamic.tiles.virtualearth.net/comp/ch/12023022311?mkt=en-US&it=G,BX,L,LA&shading=hill&og=88&n=z&c4w=1
 lassign "1095 732 11" col row zl
  set pol "12.55146 45.65106 12.54358 45.62229 12.57965 45.60649 12.60872 45.62890 12.59541 45.65461"