Geography

Coordinate

• History: 球型, 椭球形, 水准面, 空间定位
• Geodetic Datum：如何选择模型

• Coordinates: WGS84, BJ54, GDZ80 *

  http://spatialreference.org

More...

• 安全起见! GCJ02
• BD09, Mapbar...

Map Projection

将椭球面上的点通过数学法则投影到二维平面

Azimuthal Projections

Mercator

Tile System

Features

• Used in game
• Store in tree-like structure
• Pyramid coordinates

Google Map

Bing Map

Baidu Map

Layers

In GIS

In Web

Look into Code

Organize

build

dependency

doc

test

Viewport

Zoom