Torsten RahnOctober 23, 2015

Announcement: Marble ships the oldest existent historic Globe

KDE Project:

Today I have the pleasure to announce that Marble is the first popular virtual globe that ships and visualizes the Behaim Globe. The Behaim Globe is the oldest surviving terrestrial globe on earth. It was created between 1492 and 1493 - yes at the same time when Christopher Columbus made his first voyage towards the west and "discovered" America. This fact makes the Behaim Globe very special and also subject to scientific research: It documents European cartography during that era and it's probably the only historic globe which completely lacks the American continent.

These days the Behaim globe can be visited in the Germanisches Nationalmuseum in Nuremberg, Germany. The Germanisches Nationalmuseum (GNM) has kindly granted the Marble project permission to release the photo scan material of the Behaim Globe under the CC BY-SA 3.0 license and they have supported us in bringing it for the first time to the users of a widely deployed virtual globe: Marble. Right now our users can immediately download the Behaim Globe from inside Marble by entering File->Download Maps (or download it via our maps download website.).

Starting with the next Marble release scheduled for December 2015 the Behaim Globe map theme will become a regular part of the map themes that are shipped with the Marble installation package by default.

In addition the Marble project released a special Behaim Marble version in the Google Play Store. So users of Android devices – like smartphones and tablets – can enjoy the Behaim Globe, too! This also marks the first public release of a Marble based application on Android devices.
The Behaim map theme for Marble was created as part of the master thesis (Diplomarbeit) 3D Modelling of the Behaim Globe using Marble by Halimatou Poussami. The map theme allows to pan and zoom the whole Behaim Globe - curiously the whole globe is almost fully covered with detailed inscriptions in early modern German. Via checkboxes in the legend tab inside Marble our users can also overlay today's accurate coastlines. This allows to compare the Behaim cartography with today's known actual coastlines. Quite obviously the Behaim map depicts the continents stretched in longitude. So the creators of the Behaim Globe have probably based their globe on an earth radius value that was too small.

The photographic material of the Behaim Globe is based on digital scans made by the Friedrich Alexander University (FAU) in Erlangen-Nuremberg and the IPF TU Wien. These scans were performed using polarized light. This is also part of the reason for the vibrant colors that you can see in the map theme - visually the colors of the Behaim globe are much more subdued. During the past centuries the Behaim Globe has been subject to several "restoration attempts" and "editing", which also resulted e.g. in text changes. Therefore today's scientific research also focuses on the Behaim globe as a palimpsest. Using Marble's legend tab our users can compare the photomaterial of the Behaim Globe with facsimile drawings from 1853 and 1908 which also reveals differences.

The Marble Team would like to thank the Germanisches Nationalmuseum for its decision to release the Behaim imagery under the CC BY-SA 3.0 license. In particular we'd like to thank Dr. Thomas Eser (GNM), Prof. Dr. Günther Görz (FAU) and Halimatou Poussami for their active support in bringing the Behaim Globe to our Marble users and to the public!

Get it on Google Play

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Torsten RahnJune 21, 2015

GCI 2014 and Grand Prize Trip

KDE Project:

Many pre-university students have participated in Google Code-In (2014) again and for many of them it has been the first opportunity to make contributions to Free Software and Open Source projects. In opposite to Google Summer of Code the GCI program is organized as a worldwide contest where students at the age of 13-17 years take the challenge to complete as many software development tasks from their mentor organizations as possible. These software development tasks are provided by Open Source Projects that are approved as mentor organizations. And at the end of 2014 KDE has participated as a mentor organization for the fifth year.

The most recent edition of Google Code-In, GCI 2014 has again been very successful: As Heena Mahour described in her Google Code-in 2014 wrap up with KDE there have been more than 277 tasks created by KDE mentors for the students which covered all aspects of the software development cycle and which ranged from creating source code to documentation, research, quality assurance and user interface tasks. It was amazing to see how the students solved nearly all of them and helped to improve KDE applications significantly.

As in previous years the top 24 performers became Grand Prize Winners and won a trip to Google Headquarters in Mountain View, California! In the KDE community the Marble Virtual Globe developers are usually actively involved with GSOC and GCI mentorship. Two of our students - Mikhail Ivchenko and Ilya Kowalewski - have made extraordinary contributions to Marble: They had worked very hard and contributed several important features to Marble - see e.g. Mikhail's blog post about the Tour (don't miss to watch the video!) and Ilya's blog about the Measure Tool improvements. And since they also earned most points they became Grand Prize Winners.
This year I was the happy one who went to Mountain View as a KDE mentor between June 7-10. And the trip was a great opportunity to learn more about the other mentors and the winning students (they were accompanied by a parent each) and to share more about our Free Software work in the KDE project. The Grand Prize Winner trip was lovingly organized by Stephanie Taylor and other members of the Google Open Source Programs Office: It began with a meet-and-greet event on Sunday evening in San Francisco to get to know everyone. On Monday we visited Googleplex in Mountain View. And on Tuesday we had a fun day in San Francisco where we had the choice to visit the Exploratorium, Alcatraz or went on a Segway tour through San Francisco. Being a science guy I picked the Exploratorium. On Wednesday it was time to say goodbye already after enjoying another round of Googler talks, delicious food and swags at the Google San Francisco Office. The whole experience was just awesome and I'd like to thank Stephanie, Carol, Cat and all the other Googlers for organizing this event and for giving us the opportunity to join it.

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Illya KovalevskyyJanuary 1, 2015

What's going on with measures in Marble

Here in the Marble world, we are working hard on expanding the current functionality with new features. Today I would like to show you some stuff we’ve recently introduced as part of the Measure tool. The measure tool is basically a multifunctional georuler, that allows to perform a variety of measurements. For instance, now you can easily measure distances on trivial paths or areas of complicated polygon shapes.

Polygon Ruler: LondonMeasuring area and perimeter

BearingsMeasuring angles between path segments

The polygon mode has a few options to enable: distance, bearing, bearing change, area and perimeter. The bearing is an angle between the North and the direction of movement. The bearing change is basically an angle between two path segments. All values are calculated for spherical Earth, so it should work for most cases.


Circle Ruler


The Circle mode offers radius, area and circumference features here. That’s enough for most cases. In the Circle mode, you obviously can put only two points, the first is the center of the circle and the second one lies on it.

You also can switch the current mode (Polygon/Circle) and enable/disable specific features in the Measure Config Dialog: Dialog

All new features have been developed by Sergey Popov (Sergobot) and me. Needless to say, what we see now is not the final “polished” version. It obviously needs some visual UI tweaks, these will be added soon, after a massive refactoring. From other topics that are being covered at the moment, priority takes Touring, Map Editing (EgorMatirov), OSGeoLive integration & packaging (Sergobot) and of course, bug fixing.

Happy New Year!

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Illya KovalevskyyDecember 20, 2014

Why I love KStars

I always have been a huge fan of astronomy, stars, cosmos etc. I must admit that I find it absolutely breathtaking, especially, looking at particular constellations, the way they combine into jewelry shapes that have lots of similarities with known objects. Interesting, somewhere in space there could be a guy like me, looking at sky and finding other objects…


KDE Edu has an outstanding project, called KStars. It provides functionality for observing stars and constellations we have there on sky. First of all, it has a huge impact on educational programs: teachers can use it on astronomy lessons in high school. It does good calculation job and precise enough to be used in scientific researches.

At the moment, KStars has nearly 100 contributors. People has been working on it for a while and you can see a good outcome so far. Still, software can’t be perfect at all and there are always a few features in TODO list. In case if you are interested in contributing to KStars, I have good news for you, there are jobs to do. If you feel yourself rather like a beginner, don’t be afraid, there are some junior jobs as well!

So if you are not a software developer at all, don’t be upset, you always can do some testing/packaging job for different platforms KStars team, they will really appreciate it. By the way, there is a good guide about building KStars from source also, that’s a good point to start with.

Hope you will have fun with KStars!

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Illya KovalevskyyDecember 2, 2014

Google Code-In 2014 is ON!

Hey there!

Google Code-In 2014 just started and I chose KDE as my main organisation for the 3rd time I am on this contest. For those who are not familiar: GCI is an open-source development competition for students all around the world, held by Google every year. This year we have 12 organisations: Apertium, BRL-CAD, Copyleft Games, Drupal, FOSSASIA, Haiku, KDE, Mifos, OpenMRS, Sahana, Sugar Labs and Wikimedia Fundation. Everything there is around tasks, these do include:

  • Code: Tasks related to writing or refactoring code
  • Documentation/Training: Tasks related to creating/editing documents and helping others learn more
  • Outreach/Research: Tasks related to community management, outreach/marketing or studying problems and recommending solutions
  • Quality Assurance: Tasks related to testing and ensuring code is of high quality
  • User Interface: Tasks related to user experience research or user interface design and interaction

Akademy 2013 in Bilbao

I cooperate with KDE since 2012 and I must admit that it’s the most friendly and responsive community I’ve ever met so far. It’s really easy to dive in and start actually doing “a thing”. You’ll definitely get help if you need some. Just feel free to touch some people on IRC. That’s actually a powerful point of FOSS in general, you can just go on and ping a maintainer of project you are interested in. KDE is far more than just an open-source organisation, it is a Community with its own culture and habits. Just go on and google photos from latest Akademy (= key event of the year). It’s a special atmosphere and it’s really nice experience (believe me, I’ve been there).

Marble - Virtual Globe

From all KDE projects, I especially love Marble (cross-platform virtual globe) for being an outstanding project in terms of idea and implementation. It’s actually one of the most active projects on GCI upon for all time and I really appreciate what its maintainers are doing for students like me. Thanks to them I did hardly 100 commits in Marble source code tree for last years.

Open-source software development is a nice opportunity for students to participate in something big, something valuable. Software that people create here is special, because they create it for themselves and they DO have fun while doing it. In my humble opinion, the best way to start with FOSS definitely lies through KDE!

UPD: Contest just started and students already took around 30 tasks! This year is gonna be the hot one! Good luck to all students and mentors!

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Illya KovalevskyyJanuary 3, 2014

News from Marble: Planets

Hey, folks!

A few days ago we posted about new functionality added to the Virtual Globe - support of the Sun and the Moon (with appropriate phases support). Today we want to introduce planets!

In KStars you can observe any real object in the sky, starting from the Moon, finishing with Deep Sky Objects. As well as in KStars, we want alike support in Marble, so you can go deeper and try to explore not the world only, but the Sky also.

To show what Marble can do, I’d like to talk about planet conjuction in June 7: the Moon and Mars (The Moon will pass within two degrees of the the planet Mars in the evening sky. The gibbous moon will be at magnitude -12.2 and Mars will be at magnitude -0.8). Conjunctions are rare events where two or more objects will appear extremely close together in the night sky. The two bright celestial bodies will come unusually close to each other (like planets or moon), only a quarter of a degree, in the early morning sky. This rare, double-object event is definitely one not to miss. Look for the bright planets in the east just before sunrise.

In case of the Marble, you don’t need to wait until June 7, to see, how does it look like. You may just change the time control, by specifing this to correct time (in our case it is 7.6.2014).

Marble view

There is also another conjuction this year: of Venus and Jupiter. It’s date is August 18. But we won’t talk about it in terms of this article. Instead, you will have a chance to play around and experiment, as soon as we have this feature tagged and released (you will have it in master, if building from sources)! As said above: start Marble (which you can get on, set Time Control in Edit menu entry to 7 Jun 2014 and find the Moon there. You’ll find Mars as well!

You easily can turn off all or specific planet. To do such, you should find an empty space on the Sky, right-mouse click and you see context menu with all features (e.g. disabling/enabling all planets). To control specific planets, go to Configure… dialog.

We also added proper sunshading for all Planets (previously, we had it only for the Earth). For example, it’s supported by Mars. In order to prove it, we will show you two screenshots. From the Mars24 application and from the Marble (both in Flat projection). Compare them.





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Illya KovalevskyyJanuary 1, 2014

News from Marble: Introducing Sun and the Moon

Happy New Year, folks!

Here, in Marble we work a lot on new cool features, so you can play around with the Globe and explore the world more and more. Not a secret, that each minor release Marble shows great improvements in performance and features. Today I want to show you our new previously missing feature - enhanced Sun and absolutely cool support of the Moon.

For lazy people, who don’t really like reading all this news posts here is a quick overview of added stuff:

  • Gerhard Holtkamp’s astrolib is bundled to Marble core
  • Sun texture is scaled according to its real size (thanks, astrolib!)
  • Moon is rendered, moon phases are shown

Marble provides a nice opportunity to observe eclipses without even standing up from your sofa. You just go for View -> Eclipses and choose the right one (only works in master now, sorry). Here is an example of Tue Apr 29 2014:

Tue Apr 29 2014 eclipse

A quick example of moon phases support in the Marble is 23 Jan 2014, when we have the Moon, Spica and Mars around!

marble view

You would probably like to compare this to what KStars gives as output:

kstars view

Note: distances to Mars are different, because in Marble, the Moon is 4x times bigger than it should be (otherwise it’s too small and makes no sense, however this can be changed in preferences).

**Few words about moon phases (bonus) **

Moon rendering becomes not so trivial as soon as you need to reflect moon phases. It should be rotated according to its actual position also, so that’s where comes astrolib (thanks, Gerhard Holtkamp!). Final rendering process looks similar to this:

  • Rotation (Moon is rotated relatively to its current position to the Earth)
  • Scaling (by default, in Marble we use 4x aspect ratio to “real” Moon size, but you possibly would like to turn it off)
  • Moon phases overlay rendering

Let’s stop on the last step. Astrolib provides API to get information about the Moon phase in the specific moment of time:

void SolarSystem::getLunarPhase(qreal &phase, qreal &ildisk, qreal &amag)

Outputs are actual phase, illuminated disk and the apparent magnitude of the Moon reffered to the center of the Earth.

Moon phases picture

There are 8 different phases (from 1 to 8 on the picture): New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, Wanning Crescent and then it’s New Moon again. Actual rendering process is about drawing two arcs, which is not complicated, but still needs to cover all cases and calculate angles neatly. An exported paste is published here. You also can observe it right in the source code (StarsPlugin.cpp:1130; line may be different later).

Find your way and explore the world!

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Illya KovalevskyyDecember 4, 2013

KDE is the best open-source org... ever

Hello, blogey!

Today I’d like to tell you about KDE (K Desktop Environment) and how I started working on some projects there. I first met KDE 2-3 years ago when I was moving from Windows to Linux (one of the most important moments of my life, as developer). Choosing desktop environment was challenging and I thought about GNOME, which I was using for few month. Finally, I totally moved to KDE 4. I was using some nice applications, like Kate, KDevelop, Telepathy.

In the past year I heard about Google Code-In 2012. After thinking for a while I chose KDE, because it’s the most suitable organisation for me (I was working with Qt 4 smth like a year-1.5). I started working for Marble/Telepathy and that was extremely interesting. Few days later I got my KDE developer account, so I made my first commit to KDE these days.

Already, I have done relatively big amount of coding mostly for Marble - my favorite and onelove KDE application. I am participating in GCI-2013 this year also and I will do my best to improve quality of KDE in terms of UI, core stuff, user support and everything :)

For newcomers, I created a list of things you should/shouldn’t do, anyway:

  1. Don’t be aware of asking - ask as much as you need and try not to be anoying.
  2. Be creative - it’s extremely important to show yourself as creative person
  3. Try hard

P.S. I really wanna say many thanks to Dennis Nienhüser, Torsten Rahn, David Edmundson, Claudia Rauch, Lydia Pintscher and to all kde people, all gci mentors!

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