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 Hampton Roads map is done
with map tiles at OSM zoom level 12.
Approximate latitude,longitude of Hampton Roads (Newport News): 37.0708, -76.4844 degrees
Each OSM tile is a 256x256 PNG file.
Each zoom-level-12 tile is one image 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 1176 to 1180. (5 columns)
These zoom-level-12 tiles go from
y-numbers 1590 to 1597. (8 rows - extending down into Norfolk)
Total: 5 x 8 = 40 tiles
Image width: 5 x 256 = 1,280 pixels
Image height: 8 x 256 = 2,048 pixels
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Here is a link to an OSM (openstreetmap.org)
'slippy map'
for
Hampton Roads, Virginia (Wikipedia link) --- initially at zoom-level 12 and
centered at latitude and longitude 37.0708 -76.4844,
which is near the center of the city of Newport News.
Page was created 2016 Oct 31.
Page was changed 2018 May 12.
(Added 'title' hover-popups to the tile images.)
Page was changed 2018 Jul 08.
(Added 'slippy map' link.)
Page was changed 2019 Jan 11.
(Added css and javascript to try to handle text-size
for smartphones, esp. in portrait orientation.)
Page was changed 2019 Feb 10.
(HTML changes due to reorg of OSMmaps.)