Version 2 (modified by dstuebe, 13 years ago) (diff)


Cell Types For Unstructured Grid CF standard

Similar to the data types that already exist NetCDF Users Guide, we could add cell types to the netCDF library which describe the geometry of a cell. This would provide the information about how many vertices a cell has and there for how many node index values to expect in the connectivity. Each cell type would have a standard node ordering which describes how to format and use the connectivity data.

0 NC_PTS	A series of scattered points: earthquake locations
1 NC_TRK	A series of connected points: Drifter data
2 NC_LIN	An arbitrary list of lines each described by two end points: edge data

3 NC_TRI	Triangles described by the location of three vertices's
4 NC_QAD	Quadrilaterals described by the location of four vertices's
5 NC_PNT	etc
6 NC_HEX	etc
7 NC_SPT	etc
8 NC_OCT	etc
9 NC_MXD        Mixed 2D polygon cells

43   NC_TETRAHEDRON     ! Numbers are based on: #of faces #of sides     
1443 NC_PYRAMID		! for more complex types: #of faces #of sides #of faces #of sides
9999 NC_UNSTRUCT	! MIXED 3D solids cells

Better formatting?

we need good pictures to do this properly'''


  • Not sure about these 3D types:
    • other suggestions for numbering, naming, geometries?
  • Do extruded cells need an NC_XXXXX integer typing?
  • For each of these we need to define a node numbering scheme,

a face numbering scheme, and an edge numbering scheme

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