GraphHopper now also Available for Offline Routing on iOS

Today we announce the first availability of GraphHopper for iOS. It is still in an experimental shape but we would like to engage people to play with it and report issues. Go directly to the git repository and continue reading.

With GraphHopper we are in the process of building a fast and open source alternative to existing routing solutions. We provide a world wide instance for car routing, biking and walking called GraphHopper Maps. Where you can see the routing engine GraphHopper in action, combined with map tiles and address search served from other software. As GraphHopper is written in Java we already made routing possible on several platforms like Linux, Windows, Mac OS X, Raspberry Pi, Android and even offline in the Browser. But still one major platform – iOS – was missing and we thought about ways to make this possible.


The most simple solution to port a Java project these days is RoboVM. RoboVM makes a complete Android app running on iOS. Several users made their none-trivial games working with the help of RoboVM and so it should be also relative easy for an app which includes GraphHopper to be used on iOS too.


But we also wanted to have the possibility that a native iOS app can use GraphHopper as a library. And according to my investigations this is currently relative hard to achieve with RoboVM. So we decided to use the conversion tool j2objc which creates Objective-C code from Java code. The first running demo on an iPhone was made by Tobias which was a huge step in the right direction (pun intended) and really nice work! It showed the first time that it was possible at all and the dream of platform independence nearly came true. Still there were several glitches in the setup which I wanted to avoid in the first release. Tobias did not found enough time for this so I was seaking help in the GraphHopper community and I got in touch with Calin who recently had enough time and was polishing like crazy. Where ‘polishing’ means creating workarounds for j2objc bugs and using good old make to avoid Xcode limitations, telling me to fix things directly in GraphHopper, preparing a nice demo, finding bugs in other tools and the usual coder safari.


At the end he was able to produce the necessary scripts and adaptations to create a static library via j2objc and a simple-to-setup demo. Only very few so called compatibility classes had to be written in Java but Calin made it possible to completely avoid custom Objective-C code, even for the more advanced things like memory mapping. With that we can almost always automatically create the updated version out of ‘GraphHopper Java’. And GraphHopper on iOS is fast, for example a route through entire Germany takes only about 1sec on iPhone 6!

We again ask for you help and feedback!

And thanks again to Tobias & Calin!