This library is a simple JAVA / Android library that helps you transform coordinate between earth(WGS-84) and mars in China(GCJ-02).

Read this in other languages: English, 简体中文.

Geometry Utilities requires at minimum Java 7 or Android 2.3.

Convert coordinate from earth(WGS-84) to mars(GCJ-02):

Coordinate mars = GeometryUtils.wgs2gcj(39.980945, 116.348120);

Convert coordinate from mars(GCJ-02) to earth(WGS-84):

Coordinate earth = GeometryUtils.gcj2wgs(39.982296, 116.354308);

To convert coordinates from WGS to GCJ or other way back, you need to know if the coordinate is inside China mainland or not.

Common implementations use a HUGE box boundary which covers entire China Mainland and several regions like Taiwan, Hong Kong and Macau along with it to check the coordinate, which is not perfect.

To make sure you have the maximum accuracy and flexibility, Geometry Utilities provided two ways for you to achieve that goal:

By default, GeometryUtils uses a DefaultCoordinateChecker to perform the check.

The DefaultCoordinateChecker also uses a box boundary like other implementations but with Taiwan, Hong Kong and Macau excluded, which can cover most of the cases.

No additional code changes needed.

If you are still not satisfied, you can write your own implementation very easily:

public class CustomizedCoordinateChecker implements CoordinateChecker {
	@Override
	public boolean isOutOfChinaMainland(double lat, double lng) {
		// Add your own logic here
		return false;
	}
}
GeometryUtils.setCoordinateChecker(new CustomizedCoordinateChecker());

You're all set!

Copyright 2017-2019 SgrAlpha

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

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distributed under the License is distributed on an "AS IS" BASIS,
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