Reference:
http://wiki.openstreetmap.org/wiki/ Slippy_map_tilenames#Zoom_levels
Brief overview:
OSM tiles are 256x256 pixel PNG files.
Filename (URL) format is http://tile.openstreetmap.org/zoom/x/y.png
where
zoom=zoom-level-integer (from 0 to 19),
x=longitude-locator-integer (non-negative column number),
y=latitude-locator-integer (non-negative row number).
In the link above, see sample code to calculate x and y for a given zoom-level and a given latitude and longitude.
The following Mykonos Island map is done
with map tiles at OSM zoom level 12.
Approximate latitude,longitude of Mykonos:
37.45, 25.35 degrees
Each OSM tile is a 256x256 PNG file.
Each zoom-level-12 tile is one image out of
2^12 x 2^12 = 4096 x 4096 = 16,777,216 images ~ 16 million images
which are used by OpenStreetMap to cover most of the Earth.
These zoom-level-12 tiles go from
x-numbers 2334 to 2338. (5 columns)
These zoom-level-12 tiles go from
y-numbers 1585 to 1589. (5 rows)
Total: 5 x 5 = 25 tiles
Image width: 5 x 256 = 1,280 pixels
Image height: 5 x 256 = 1,280 pixels
These tiles are fetched from the
OSM server when you (re)load this page.
So these tiles form an image using
the latest versions of the OSM tiles.
Here is a link to an OSM (openstreetmap.org)
'slippy map'
for
Mykonos (Wikipedia link) --- initially at zoom-level 12 and
centered at about latitude and longitude 37.45, 25.35,
which is near the center of the island.
Page was created 2019 Feb 12.