A cross-section group includes a cross-section entity defined by the river/reach combination in which it is associated. Cross-sections are also associated with profile lines by these names. They reference the cross-section geometry (D,X,Y,Z values). Cross-section properties include the type of spatial reference (point, 2D line, or 3D line) and the spatial referencing entity. Because a cross-section may have many point or line properties, but each point or line property has only one cross-section they are not referenced directly by the cross-sections. Instead each point and line property references the cross-section.
The cross-section geometry is a 3-dimensional array (number of cross-sections, by max number of d-z pairs, by 2) that hold the D,Z pairs for each cross-section. The geometry of a cross-section defined by a 3D line could be stored in the cross-section geometry, or it could be left out with the calling application generating the geometry "on the fly," as needed.
Figure 10 Cross-sections
