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The SEDRIS Data Representation Model
APPENDIX A - Classes Property Grid Hook Point |
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An instance of this DRM class is used to "instance" a <Property Grid> into the spatial scope of an <Environment Root> or <Model>. In particular, the origin of the spatial axes of a component <Property Grid> is located at the <Property Grid Hook Point>'s component <Location>.
Since a <Property Grid Hook Point> separates a <Property Grid>'s cell data from the <Location> of its origin, <Property Grid> instances can be shared by several <Property Grid Hook Point> instances.
Consider a 1-dimensional <Property Grid> classified as ECC_WATER_BODY_BATHYMETRY_PROPERTY_SET that contains a depth axis only. The <Property Grid Hook Point> <Location> serves to position this grid into the currently scoped 'world' spatial reference frame.
Consider a 2-dimensional <Property Grid> classified as ECC_TERRAIN_ELEVATION that contains elevation relative to the south-west corner of the grid. The <Property Grid Hook Point> <Location> serves to position this grid corner into the currently scoped 'world' spatial reference frame.
No, the hook point <Location> serves several purposes.
Since the spatial axes are relative, the hook <Location> provides the axis offset origins.
It makes a <Location> associated with the grid visible to API search filters (in the currently scoped 'world' spatial reference frame).
An association between a <Geometry Hierarchy> instance and a <Feature> instance indicates that the <Geometry Hierarchy> and the <Feature> are alternate representations of the same environmental object.
An association between two <Geometry Hierarchy> instances indicates that they are alternate representations of the same environmental object.
An association from a <Hierarchy Summary Item> instance to a <Geometry Hierarchy> indicates that the <Hierarchy Summary Item> summarizes that <Geometry Hierarchy>.
An association from a <Reference Surface> instance to a <Geometry Hierarchy> indicates that the <Geometry Hierarchy> organizes the geometric objects that specify the resolution surface of the <Reference Surface>.
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