Exploring the globe with Marble 1.1

Marble, as part of the KDE Software Collection (KSC), typically sees releases in-line with major KDE releases. However, thanks to the efforts of students working with the KDE Project for the Google Code-in, Marble picked up enough new features that it was worth releasing 1.1 mid-cycle and getting its new features out early. With 1.1 the 3D mapping application picks up plugin configuration, map editing, and voice navigation if you happen to be using Marble on the Nokia N900.

Marble is 3D virtual globe, part of the KDE application set — but also available in a Qt-only version for Linux users who prefer not to include KDE-only dependencies or for Mac and Windows users. Since LWN last looked in on Marble, it's come a long way. The basic interface is still the same — but Marble has picked up quite a few features since the 0.5 days.

Since 1.1 is out of step with KDE SC releases, it may not turn up as a package for any of the major distributions right away. To test it out, I decided to compile it from source on openSUSE 11.4. As mentioned, you have the choice of compiling the Qt-only version of Marble or the full KDE version — I opted for the full KDE version. The 1.1 release library is meant to be ABI compatible with the 1.0 release, which means that other KDE applications that depend on it should work as expected.

One word of warning if you do opt to compile Marble on your own — make sure to uninstall the prior Marble package as well. Forgetting this simple and obvious step could lead to some odd behavior, or so we've heard.

Using Marble 1.1

After compiling Marble 1.1, I set about exploring the Marble interface and checking out some of the new features. For exploring the globe and generally poking around, Marble is fantastic. The interface is easy to use, it offers a variety of map views (flat, Mercator projection, and your standard globe), and quite a few themes. The themes are things like a satellite view of Earth, OpenStreetMap (OSM) data, Earth at night (which shows city lights from space), and so on.

Marble is a good tool for students, hence its position in the KDE Educational software project. You can click on a city and see two tabs. One contains the Wikipedia entry for the city and the other contains a basic data sheet provided with Marble itself — though I found no description in any of the data sheets for any of the cities that I checked. Each had coordinates, country, time zone, etc., but Marble seems to rely on Wikipedia for any actual description.

One of the interesting new features in Marble 1.1 is an online service that displays earthquakes that have happened in a given spot with their magnitude. It's worth noting that this feature was completed during the Code-in and is not related to or inspired by the earthquakes that caused so much damage in Japan. It was surprising to see just how many earthquakes that have been recorded in the US Midwest, though of minor magnitude, since 2006. Unfortunately, Marble doesn't provide a link to any additional information about the events online — the data is simply provided as a colored circle with the magnitude. The color and size of the circle is determined by the magnitude of the earthquake, with larger quakes being a darker red and having a larger diameter. Hovering the mouse over the circle will display the date and depth — but that's all.

For users who have a Nokia N900, Marble should provide voice navigation. Unfortunately, I don't have a Nokia N900 handy, and wasn't able to test this feature. Users who are interested in voice navigation will need to convert a TomTom voice for use with Marble, as it doesn't ship with any at the moment. The Marble folks would welcome contributions, so if you're a non-developer with a pleasant voice this may be an opportunity to contribute.

Marble will open maps or map data in GPS Exchange Format (GPX) and Keyhole Markup Language (KML). I didn't do a lot with importing GPX or KML map data, but did grab a few GPX files online and viewed them in conjunction with OpenStreetMap data. This seemed to work very well.

Where Marble falls down a bit is with routing. Marble allows you to search maps for street addresses and create routes between addresses, but tends to be hit or miss when it comes to actually creating a route or finding some street addresses. For example, I tried creating a route between my home in St. Louis and Bradenton, Florida or between my home in St. Louis and my parents' old home less than 100 miles from St. Louis. Between St. Louis and Florida, Marble was unable to generate a route at all. Marble was also unable to find my old home address, though I could create a route from my current address to my old hometown that was mostly sane.

At home cartography

One of the major new features for 1.1 is the ability to edit maps or create your own. Users can import map data from a server that provides data via Web Map Service (WMS), via a bitmap stored locally, or from a static service like OSM.

The process is laid out in a tutorial on the KDE UserBase, but is not terribly intuitive as of yet. It does work, it's just a bit clunky and certainly will be non-obvious to most users. The tutorial also provides a few pointers for WMS servers and other resources, which will be useful to anyone who wants to learn how to make a map without already having a free map service in mind. According to Dennis Nienhüser, one of the Marble developers, an updated (and more intuitive) wizard is on its way for Marble 1.2.

When using OSM maps, users can actually right-click on the map and open it in an external editor to edit the map. Marble supports a Flash-based editor called Potlatch, along with Merkaartor, or JOSM for editing maps.

Up the Marble road

Though the 1.1 release was pushed out so the world could have the new features early, one shouldn't worry that Marble 1.2 won't hit on schedule. The 1.2 release will be back in sync with the KSC release, so it's expected with the KDE 4.7 release scheduled for July. One of the things that is on the drawing board is an OpenGL mode for Marble. This doesn't mean that Marble would leave 2D systems behind — but it would add OpenGL support for platforms that have it enabled.

Nienhüser also says that more mobile platforms are in the future for Marble, as well as making Marble one of the "Plasma Active" enabled applications. Which mobile platforms? Nienhüser says he's looking at MeeGo first, and "if MeeGo does not kick off, I guess Android is the next target."

Marble also has a couple of Google Summer of Code projects in the works, according to Nienhüser. One is vector rendering of OSM data (it's currently using bitmapped data — which requires quite a hefty download), the other is a QML version of Marble that would target MeeGo.

Though it's still rough around a few of the edges, Marble has come a very long way since its early days — and looks to be headed for uncharted territory as one of the most usable free software mapping tools.