Changes between Version 3 and Version 4 of UgCellArrays


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Timestamp:
11/17/06 13:55:49 (12 years ago)
Author:
tomgross
Comment:

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  • UgCellArrays

    v3 v4  
    33
    44This is an example of a CDL based a simple hierarchy of geometric objects:
     5 node:: The 1d geometry point.  A location.
     6 edge:: Simple line segments, defined by two locations
     7 face:: An area defined on a cell
     8 cell::  An object with corners, edges and faces.  May or may not be three dimensional.
    59 grid::  A collection of cells
    6  cell::  An object with corners, edges and faces.  May or may not be three dimensional.
    7  edges:: Simple line segments, defined by two locations
    8  faces:: An area defined on a cell
    9  nodes:: The 1d geometry point.  A location.
     10 mosaic:: A collection of grids with connectivity information
     11 track:: A collection of edges.  Used to describe coastlines, boundaries or interior elongated objects like roadways or levees.
    1012
    11 A simple cell is defined by the indices which call out which nodes, edges, faces comprise the cell.  In this strawman CDL case the simple cell for the grid will be a triangle defined by three nodes and having some variables specified at edges and the central face  of the triangle.  Below in the grid meta data I call this "tri_face_edged" .
     13A simple cell is defined by the indices which call out the nodes, edges, and faces that comprise the cell.  In this strawman CDL case the simple cell for the grid will be a triangle defined by three nodes and having some variables specified at edges and the central face  of the triangle.  Below in the grid meta data I call this "tri_face_edged" .
    1214
    13 The data set will consist of a grid of cells.  The index array for the grid will dimensioned to the number of cells.  The data set will also consist of a collection of nodes, defined by their spatial location.  The data set will also contain a collection of edges.  Edges are defined by two nodes.  Edges must have a direction associated with them, so it is necessary to define an edge independent of the two different cells which it may be part of.   So, grid(icell,:) provides the indices to all the other data:
     15The data set will consist of a grid of cells.  The index array for the grid will be dimensioned to the number of cells.  The data set will also consist of a collection of nodes, defined by their spatial location.  The data set will also contain a collection of edges.  Edges are defined by two nodes.  Edges must have a direction associated with them, so it is necessary to define an edge independent of the two different cells which it may be part of.   So, grid(icell,:) provides the indices to all the other data:
    1416 * grid(icell, :) = [ 4 5 8 2 3 4 10 ]
    1517 * The triangle is defined by lon([4 5 8]), lat([4 5 8])