Introduction to Atlantis
Last updated on Tuesday, June 8, 2010 - 07:12

The main features of the Atlantis event display

  • The use of data oriented projections
  • The use of subviews within the display area to be able to view various projections simultaneously
  • 2D animations beyond panning and zooming
  • 3D synchronous pointers across the various projections, so you may pick an object in one projection and see where it is located in the other projections
  • A basically mouse driven user interface using generally applied facilities of modern user interfaces (e.g. pop-up, tooltip). It consists of a control window "Atlantis GUI", a display area window "Atlantis Canvas" and various pop-up windows


Data visualised by Atlantis

  • 3D silicon space points, silicon strip clusters and TRT straws
  • Simulated tracks, neutral particles and vertices
  • Multiple collection of reconstructed tracks (Track)
  • LAr, Tile, HEC and FCAL calorimeter cells and calorimeter clusters
  • Muon data including MDT, RPC, TGC, CSC hits and CSC clusters
  • Simulated and reconstucted muon tracks
  • AOD datatypes - Bjet, Tau, Electron, Muon, etc
  • associations between datatypes (hits-to-Track, Track-to-Vertex, etc)


Projections and Data

In the program a distinction is made for data in 3D space between space points (e.g. silicon hits) and space lines (e.g. straws from the TRT). All projections may be used for both types of data. The following list presents the most appropriate projections for various datatypes:

  • YX - TRT, LAr and TILE barrels, RPC, vertex region (intuitive view)
  • φρ - TRT, LAr and TILE barrels, RPC, tracks are straight lines
  • ρZ - Barrel and endcap calorimeters
  • X'Z - MDT, RPC and CSC, vertex region (intuitive view)
  • Y'Z - Orthogonal view to X?Z
  • φZ - TRT endcaps, calorimeter endcaps and TGC
  • φη - Calorimeters, and their association to tracks and S3D hits
  • 3DBox - Vertex structure of tracks near the primary vertex
  • Lego - Calorimeter lego towers and Jets

Projections and magnetic field - depending on the projection and the type of magnetic field, tracks of charged particles will be more or less straight. The following list gives an overview:

  • YX curved in solenoidal field
  • YX almost straight in toroidal field
  • φρ curved in solenoidal field
  • φρ almost straight in toroidal field
  • φZ curved in solenoidal field
  • φZ almost straight in toroidal field
  • ρZ almost straight in solenoidal field
  • ρZ curved in toroidal field

User Interface

The Atlantis user interface is basically mouse driven and using generally applied facilities of modern user interfaces (e.g. pop-up, tooltip). It consists of a permanent control window - Atlantis GUI, a display area window - Atlantis Canvas and various pop-up windows.

The Atlantis control window used to view and modify parameters and selections that control the pictures on the Canvas. Functionality is grouped into components, namely (listed from the top to the bottom of the window):

  • Menu - Provides functionality for I/O, program customisation and the help system
  • Canvas Control - Provides functionality for Canvas window management (copy, zoom, pop-up menus, etc.) in the display area or Canvas
  • Interaction Control - Provides functionality for user interaction with the program (pick, zoom, transformations, projections)
  • Parameter Control - Provides functionality for viewing and changing various parameters (data selection, cuts, detector, subdetector systems, projections)
  • Info output - Displays output of the program (picking output, cuts summary, etc.)

The Canvas is the place where Atlantis draws it's pictures. Shape and layout of the Canvas are variable. The use of subviews is very useful to have various projections displayed simultaneously.

The pop-up windows are available for quick viewing and modification of parameters and selections.

The entire structure of the interface is defined in an XML file and is read in at startup. This allows custumization of the graphical user interface.


Access to Events

Atlantis reads in event data in the XML format. XML event files are produced by the JiveXML algtool which runs in the Athena framework. Instructions for running JiveXML can be found here . A set of example XML event files is included in the Atlantis distribution.

Atlantis can read XML event files from three sources:

  • offline and most common mode where events are read in from XML files stored locally, i.e. on the machine where Atlantis is started from
  • online mode - events are loaded via network link between remote machine running Athena/JiveXML and local machine running Atlantis
  • from URL


Detector Geometry

Atlantis uses detector geometry to convey quickly to the user the context in which measured data are seen. For such a purpose an idealized detector geometry is both adequate and desirable. The geometry description is stored in two seperate XML files in the geometry directory within the Atlantis distribution:

  • AGeometry.xml - inner detector and calorimetry
  • AMuonGeometry.xml - muon system geometry derived from AGDD

These two files are again produced by the JiveXML algtool (resp. by GeometryJiveXML). The geometry of some subdetectors was enlarged in the idealised geometry to make them visible on the display. E.g. the width of the LAr presampler (1 cm) was increased, since it would have been invisible if drawn as such.