Tiles à la Google Maps
Coordinates, Tile Bounds and Projection
How does a zoomable map work?
People are using coordinate systems and map projections to transform the shape of Earth into usable flat maps for centuries.
A map of the entire world is too big to be directly displayed in a computer so there is a clever mechanism for quick browsing and zooming on maps: the map tiles.
The world is divided into small squares, each with fixed geographic area and scale. This clever trick allows you to browse just a small part of the planet without loading the whole map - and you still get an illusion of exploring a single huge document.
Pioneered by Google, now standardized.
Google Maps was one of the first systems displaying dynamic maps on the web. They chose a Spherical Mercator projection because it preserves shape and angles. The entire world looks like a square, which makes it easy to work with on a computer.
Almost every open source and commercial Maps API providers as well as OpenStreetMap and MapTiler Cloud Maps APIs are now using this projection and tiling profile and the tiles are therefore compatible with each other.
Convert coordinates for using global map tiles
Degrees Geodetic coordinates WGS84 (EPSG:4326)
Longitude and latitude coordinates used by GPS devices for defining position on Earth using World Geodetic System defined in 1984 (WGS84).
HINT: WGS84 geodetic datum specify lon/lat (lambda/phi) coordinates on defined ellipsoid shape with defined origin ([0,0] on a prime meridian).
Meters Projected coordinates Spherical Mercator (EPSG:3857)
Global projected coordinates in meters for entire planet. Used for raster tile generation in GIS and WM(T)S services.
HINT: Simpler spherical calculation are used instead of ellipsoidal. Mercator map projection deforms size (Greenland vs Africa) and never shows poles.
Pixels Screen coordinates XY pixels at zoom
Zoom-specific pixel coordinates for each level of the pyramid. Top level (zoom=0) has usually 256x256 pixels, next level 512x512, etc.
Devices calculate pixel coordinates at defined zoom level and determine visible viewport for area which should be loaded from servers.
Tiles Tile coordinates Tile Map Service (ZXY)
Coordinates of a tile in the pyramid. There is one tile on the top of the pyramid, than 4 tiles, 16 tiles, etc. All tiles have the same size, usually 256x256 pixels.
Only the relevant tiles loaded and displayed for the area of interest / viewport.
MapTiler Platform as a full online mapping solution
MapTiler makes it easy to create and self-host maps for your websites and products. If you are a newbie you couldn't care about complicated cartography things, MapTiler solves it for you. But it isn't mean that it is deprived of advanced functions for experts.Download the software Try online map cloud
Resolution and scales
List of resolutions and scales of pyramid in Spherical Mercator projection
|Zoom level||Resolution (meters / pixel)||Map Scale (at 96 dpi)||Width and Height of map (pixels)|
|0||156,543.0339||1 : 591,658,710.90||256|
|1||78,271.51696||1 : 295,829,355.45||512|
|2||39,135.75848||1 : 147,914,677.73||1,024|
|3||19,567.87924||1 : 73,957,338.86||2,048|
|4||9,783.939620||1 : 36,978,669.43||4,096|
|5||4,891.969810||1 : 18,489,334.72||8,192|
|6||2,445.984905||1 : 9,244,667.36||16,384|
|7||1,222.992452||1 : 4,622,333.68||32,768|
|8||611.4962263||1 : 2,311,166.84||65,536|
|9||305.7481131||1 : 1,155,583.42||131,072|
|10||152.8740566||1 : 577,791.71||262,144|
|11||76.43702829||1 : 288,895.85||524,288|
|12||38.21851414||1 : 144,447.93||1,048,576|
|13||19.10925707||1 : 72,223.96||2,097,152|
|14||9.554728536||1 : 36,111.98||4,194,304|
|15||4.777314268||1 : 18,055.99||8,388,608|
|16||2.388657133||1 : 9,028.00||16,777,216|
|17||1.194328566||1 : 4,514.00||33,554,432|
|18||0.597164263||1 : 2,257.00||67,108,864|
|19||0.298582142||1 : 1,128.50||134,217,728|
|20||0.149291071||1 : 564.25||268,435,456|
|21||0.074645535||1 : 282.12||536,870,912|
|22||0.037322768||1 : 141.06||1,073,741,824|
|23||0.018661384||1 : 70.53||2,147,483,648|
EPSG.io - Coordinate systems worldwide
Open Source project for visualisation of all coordinate system of a world. Convert coordinated online, get coordinates from a map in different projections, browse the coordinate database.
Look at Spherical mercator in EPSG.io
Transform coordinates from WGS84 to EPSG.io