Understanding Coordinate Systems:

• WGS84: World Geodetic System, used by GPS devices and services like Google Maps API.
• GCJ02: "Mars Coordinates", a Chinese encryption algorithm that adds random offsets for security reasons.
• BD09: Baidu's coordinate system, based on GCJ02 with additional transformations.

How to use this tool:

1. Enter your coordinates in the input box (longitude,latitude format)
2. Select the source coordinate system
3. Choose the desired precision (decimal places)
4. Click "Convert" to transform to all coordinate systems
5. Click "Copy" next to any result to copy to clipboard

This tool is especially useful when working with maps in China or with Chinese services, where coordinate system differences can lead to significant positioning errors.