Warning, /education/marble/MANIFESTO.txt is written in an unsupported language. File is not indexed.

 
 MARBLE - MANIFESTO 
 
 Principles and intentions of the Marble Project
 
 
 v.0.3.2, April 12th, 2007
 
 
 Virtual Globes have existed since decades already and have been
 subject of numerous papers in scientific research.  Although many of
 them had been available for personal computers they only recently
 gained the awareness of public interest: Google Earth suddenly allowed
 people to spot their houses' roofs free of charge from high above and
 enabled them in combination with Google Maps to show their Google
 Search Queries referenced on a geographical map.  Almost instantly
 Google Earth had become the "industry leader" among virtual globes
 that others had to measure up to [1].
 
 
 Why Marble?
 ===========
 
 Today there exist numerous virtual globes and the market has embraced
 strong contenders such as Google Earth/Maps, MS Virtual Earth 3D and
 NASA WorldWind [2]. A new virtual globe project must be able to offer
 strong selling points and has got to focus on those without
 compromises. Otherwise it simply won't gain public relevance.
 
 "Where?" is a pretty basic question that computer users have got to
 ask and answer quite often - no matter what they are working on.  The
 free desktop has been advancing since years already.  And while
 there's a pretty large amount of free software GIS ("Geographical
 Information System") applications available [3] they are mostly
 targeted at advanced users who deal with geo data during their daytime
 jobs or as a matter of enthusiasm.  However, most people out there
 aren't cartographers and don't want to be.  These people expect a
 simple and clean task-oriented interface that adheres to the map
 layout standards that decades of cartography have developed to improve
 ease of use of maps.
 
 So for casual users there is still missing a fast, flexible, visually
 pleasing and easy to use map component.  For developers, Marble offers
 a light-weight, fast, cross platform map component that can be used
 online as well as offline with meaningful results and that don't
 require proprietary webservices.
 
 Marble is meant to become for "geo browsers" what KHTML/WebKit is for
 web browsers already.
 
 From an average user's point of view a map component such as "Marble"
 should meet the following requirements:
 
 1.  FAST: 
 
     To allow instant access and usage as a widget the Marble Widget
     should start up instantly and be ready for use within 2-3
     seconds.  So "application" startup time should always be kept as
     low as possible.
 
     Technically this means that the Marble Widget needs to be heavily
     optimized for start up times and should have a minimal number of
     dependencies (as an increasing amount of libraries will slow down
     the application's launch).
 
     Most other virtual globes have startup times of 15-30 secs.
     That's just an eternity to wait for if you just want to look up
     something.
 
 
 2.  VISUALLY APPEALING: 
 
     The maps drawn by Marble Widget should adhere to visual
     cartographic standards and should look appealing.  Usually people
     prefer the 3D globe view as it looks more natural, mostly because
     of minimal distortion and because it looks more "advanced". It
     should be possible to easily print the maps and to embed them into
     documents without getting a pixel mess that is hard to decipher.
 
     Most other virtual globes don't offer good printing support and
     the graphical representation most of the time is just limited to
     satellite views that are often labeled pretty badly. Web based
     solutions (such as Google Maps) are quite static in their
     appearance and are limited in terms of possible modification.
 
 
 3.  EASE OF USE: 
 
     Another very important aspect is usability: The feature set should
     cover the use cases of the primary target user only.  3D flights
     are pretty exciting for users that want to be entertained.
     However most users don't need them, don't have the time to
     experiment with them or don't even discover that feature.  So
     focusing on the top-bottom view exclusively ("2.5D") makes sense
     for Marble.
 
     Maps should be easy to read.  In a lot of cases this will mean
     that the flat projection ("equirectangular projection" / "plate
     carrée") is more convenient (e.g. in a timezone chooser dialog).
 
     I personally consider Google Earth's interface too complex for
     most users we are aiming for.  Google Maps on the other hand seems
     too simple to me and also has a slight annoyance factor due to its
     web based nature.
 
 
 4.  MINIMAL HARDWARE/SOFTWARE REQUIREMENTS:
 
     The Marble Widget should work at usable speed out of the box on
     all possible hardware the desktop environment is running on.  It
     should always show exactly the same output independent of the
     hardware.  During installation modifications to the system should
     stay as low as possible.
 
     This is an important point as people will simply neglect a
     solution if it's too painful to install or results in other
     unnecessary challenges during configuration.  Unfortunately many,
     if not most, computer systems out there don't offer decent 3D
     hardware acceleration for graphics.  So the solution we are aiming
     for should not depend on 3D hardware acceleration, although we
     certainly might want to offer solutions such as an OpenGL backend
     as an option.  Also the amount of software needed to install the
     map component should stay as low as possible (see 1.) ).
 
 
 5.  OFFLINE USAGE: 
 
     The Marble Widget should offer a minimal data set that is
     specifically edited and compiled for offline usage.  This is
     especially useful in countries where internet access is restricted
     or expensive.  Online usage should cover incremental downloading
     of texture tiles, vector data (e.g. OpenStreetMap) and wikipedia
     articles.
     Concerning offline geographical data Marble intends to deliver the 
     "biggest bang for the byte" and provide as much high quality 
     information per byte as possible.
 
     For all information that goes beyond map labels ("Marble Almanac")
     we have started cooperation with the Wikipedia Offline Reader
     Project.
 
 
 6.  FREE SOFTWARE & OPEN STANDARDS: 
 
     The Marble Widget is free software and should use a small set of
     open standards for communication with other applications at
     runtime and to save data to the storage medium.  The open KML file
     format[4] used by Google Earth is probably the most popular file
     format these days to geo reference data.  Through "feeding" KML
     streams to the map component, applications are offered a simple
     "programming" interface to control the map's appearance and
     behaviour.  All Information displayed on the map widget should be
     covered by free licenses using sources such as NASA or
     OpenStreetMap.
 
     Many other virtual globes are proprietary and are using commercial
     geo data that is considered "non-free" (as it isn't freely
     redistributable).
 
 
 The Marble Universe
 ===================
 
 Apart from the Marble Widget (which is implemented using the Qt4.2
 library only) there are other planned member components of the Marble
 universe:
 
 1. "Marble Desktop Globe": 
 
     KDE 4 application for KDE-EDU: This "reference" application is
     meant to show off much of Marble's full potential.  At the current
     point of time it's the next logical step as educational
     applications don't need to cover the data in full detail to be
     useful.  Once it reaches maturity the Marble backend could be
     moved into a more central place, e.g. kdelibs/base.
 
 2. "Marble Widget":
 
     Can be used in different applications like KStars, KControl,
     DigiKam, KGeography, Kopete, Addressbook, Risk-Game, KWorldClock,
     Traceroute, Plasma Weather Applet, and so on. Depending on the use case
     it can have different appearances:
      - "normal" widget
      - selection dialog
      - developer mode
 
 3. "Marble Framework":
 
     A framework of geo services for the desktop. This should cover a
     "position provider" backend like GPS, hostip.info, track turtle,
     and information services ( "Marble Almanac" ).
 
 
 Torsten Rahn
 
 
 References:
 
 [1] as an interesting read see the discussion section at
     http://www.earthslot.org/vgconference/VGconference_results.php
 
 [2] for a nice introduction into virtual globes and a
     non-comprehensive list of them see the article at Wikipedia
     http://en.wikipedia.org/wiki/Virtual_Globe
 
 [3] www.freegis.org provides a nice software overview on Free
     Geographic Information Systems
 
 [4] KML 2.1 Reference available at:
     http://earth.google.com/kml/kml_tags_21.html