# 5.2 Topology and Geometry

Topic Version | 1 | Published | 09/11/2015 | |

For Standard | RESQML v2.0.1 |

For an optimized design and to support workflow flexibility, topology, geometry, and properties are handled differently than in the hierarchical approach of RESQML v1.

To support partial model updates, the topological description of a data object has been separated from its properties. This construction is consistent with the knowledge hierarchy explained above, in which a description of a feature without properties is an interpretation, while a representation is required for property data. This construction is also similar to how seismic data is stored in SEGY, with the seismic trace headers and header information separated from the seismic trace records and data.

The table below (also repeated here from Chapter 3 Organization and Key Concepts: Overview , for convenience) defines these terms and points to more detailed chapters.

Term |
Definition |
---|---|

Topology |
Each representation contains a topological description, which defines how to associate nodes and other “indexable elements” to represent points, lines, surfaces or volumes (like structured and unstructured grids). For complex objects like simulation grids, much of the topological description can be implicit. For more information about indexable elements, see 6.2 Indexing and the RESQML Technical Reference Guide. |

Geometry |
Each representation contains its geometry, which is the spatial location of each selected indexable element, mainly nodes. This information may be provided as numerical arrays stored in HDF5 datasets, or specified implicitly. Geometry may be contained within a representation (as just described) or, if not used to define the geometry of a representation, implemented as a “point property”. For more information about geometry, see 7 Geometry ) |