H3-Java

This library provides Java bindings for the H3 Core Library. For API reference, please see the H3 Documentation.

Usage

Add it to your pom.xml:

<dependency>
    <groupId>com.uber</groupId>
    <artifactId>h3</artifactId>
    <version>4.1.0</version>
</dependency>

Or, using Gradle:

compile("com.uber:h3:4.1.0")

Encode a location into a hexagon address:

H3Core h3 = H3Core.newInstance();

double lat = 37.775938728915946;
double lng = -122.41795063018799;
int res = 9;

String hexAddr = h3.latLngToCellAddress(lat, lng, res);

Decode a hexagon address into coordinates:

List<LatLng> LatLngs = h3.cellToGeoBoundary(hexAddr);

Supported Operating Systems

H3-Java provides bindings to the H3 library, which is written in C. The built artifact supports the following:

Operating System	Architectures
Linux	x64, x86, ARM64, ARMv5, ARMv7, PPC64LE, s390x
Windows	x64, x86
Darwin (Mac OSX)	x64, ARM64
FreeBSD	x64
Android	ARM, ARM64

You may be able to build H3-Java locally if you need to use an operating system or architecture not listed above.

Development

Building the library requires a JDK, Maven, CMake, and a C compiler. To install to your local Maven cache, run:

mvn install

To build the library, run:

mvn package

To format source code as required by CI, run:

mvn com.spotify.fmt:fmt-maven-plugin:format

Additional information on how the build process works is available in the build process documentaiton.

Building on FreeBSD

# To install build dependencies
sudo pkg install openjdk11 maven cmake bash
# Ensure /usr/local/openjdk11/bin is on your path

Javadocs

To build Javadocs documentation:

mvn site

Then open the file target/site/apidocs/index.html.

Benchmarking

To run benchmarks, either execute them from IntelliJ or run the following from shell: (Replace the class name as needed)

mvn exec:exec -Dexec.executable="java" -Dexec.args="-classpath %classpath com.uber.h3core.benchmarking.H3CoreBenchmark" -Dexec.classpathScope="test"

Contributing

Pull requests and Github issues are welcome. Please see our contributing guide for more information.

Before we can merge your changes, you must agree to the Uber Contributor License Agreement.

Legal and Licensing

H3-Java is licensed under the Apache 2.0 License.

uber/h3-java