Changes between Initial Version and Version 1 of MeshMetaData


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Timestamp:
10/31/06 11:35:07 (13 years ago)
Author:
dstuebe
Comment:

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  • MeshMetaData

    v1 v1  
     1= Mesh !MetaData =
     2
     3== Where should the Mesh !MetaData Reside? ==
     4The connectivity variable of each mesh could contain the mesh meta data for each mesh in the file. If a file has three meshs (for instance: Bathymetry, Sea Surface Height, and Data) then there would probably need to be three connectivity variables anyway to describe them. The one-to-one nature makes this variable an obvious choice. The names of all the meshes in a file should be specified in GlobalAttributes. These names should corrispond to the name of the connectivity variables.
     5
     6
     7== What should be included in the Mesh !MetaData? ==
     8 * Spatial Dimension and Topology
     9 * names of coordinate variables
     10 * name of coordinate type
     11 * Cell type (types)
     12
     13== Discussion ==
     14
     15=== Spatial Dimension and Topology ===
     16
     17''' Spatial Dimension ''' ::
     18  ''The spatial dimension attribute corresponds to how many dimensions are needed to specify the coordinates for the points that make up your mesh. If your mesh exists in a 2D plane then choose 2, otherwise choose 3.'' '''Quote:''' [http://www.llnl.gov/visit/manuals.html LLNL's VisIt]
     19
     20''' Topological Dimension ''' ::
     21  ''The Topological dimension attribute describes the number of logical dimensions used by your mesh, regardless of the dimension of the space that it sits in. For example you may have a planar suface of triangles sitting in 3D space. Such a mesh would be topologiacally 2D even though it sits in 3D space. The rule of thump that Visit follows is that if your mesh's cells are points then you have a mesh that is topologically 0D, lines are 1D, surfaces are 2D volumes are 3D.'' '''Quote:''' [http://www.llnl.gov/visit/manuals.html LLNL's VisIt]
     22
     23=== Name of Coordinate Variables ===
     24The name of the coordinate variables used define to location of points in a mesh should be specified in the mesh meta data. This will prevent confusion in the case that there is more than one set of coordinate locations in a file to support more than one mesh.
     25
     26=== Name of Coordinate Type ===
     27There are a number of different coordinate types in use. Which type the mesh uses should be specified in the meta data. Some examples include:
     28 * z-coordinates vs sigma-coordinates
     29 * lat/lon vs projection
     30The types should be enumerated and standardized as part of the Unstructured Grid convention?
     31
     32=== Cell Type ===
     33see CellType
     34
     35== Example CDL for the connectivity variable ==
     36
     37=== Two dimensional triangular Mesh ===
     38{{{
     39int     MESH A(nConnect_A, nCells);
     40        MESH A:Standard_Name      = "Connectivity"
     41        MESH A:Spatial Dimension  = "3"
     42        MESH A:Topological Dimension = "2"
     43        MESH A:X nodal coordinate = "x_A"
     44        MESH A:Y nodal Coordinate = "y_A"
     45        MESH A:Z nodal Coordinate = "Z_A"
     46        MESH A:Cell Type       = "NC_TRI"
     47}}}
     48
     49=== Extruded two dimensional triangular mesh ===
     50{{{
     51int     MESH B(nConnect_B, nCells) ;
     52        MESH B:Standard_Name      = "Connectivity"
     53        MESH B:Spatial Dimension = "3"
     54        MESH B:Topological Dimension = "3"
     55        MESH B:X nodal coordinate = "x_B"
     56        MESH B:Y nodal Coordinate = "y_B"
     57        MESH B:Sigma_Coordintes   = "Sigma"        ! Name of sigma coordinate variable
     58        MESH B:Sigma_surface      = "Surface"      ! Name of surface height variable
     59        MESH B:Sigma_bottom       = "Bottom"       ! Name of sigma bottom depth variable
     60        MESH B:Sigma_equation     = "Your equation here"
     61        MESH B:Cell Type       = NC_tri
     62}}}
     63
     64=== Mixed three dimensional cell mesh ===
     65{{{
     66int     MESH C(nConnect_C, nCells) ;         
     67        MESH C:Standard_Name      = "Connectivity"
     68        MESH C:Spatial Dimension = "3"
     69        MESH C:Topological Dimension = "3"     
     70        MESH C:X nodal coordinate = "x_C"   
     71        MESH C:Y nodal Coordinate = "y_C"
     72        MESH C:Z nodal Coordinate = "Z_C"
     73        MESH C:Cell Type       = "NC_UNSTRUCT"
     74        MESH C:Mixed Cell List = "Mesh C Types" 
     75}}}
     76
     77'''Go Back to''' CdlDiscussion '''Table of Contents'''