The ISO 19100 series of standards, like many other GIS frameworks, empha= sizes 2D spatial coordinates with various reference frames which are fixed = to the rotating earth. There is, however, some nominal functionality define= d to support 3D geometric constructs. This page is a challenge to figure ou= t how to represent one of the simplest 3D constructs using the framework pr= ovided by ISO 19107.

=20For the coverage effort, there is a need to define a grid cell with thre= e spatial dimensions which is bounded by grid points at the corners. For in= stance, the grid cell occupying the volume between (0, 0, 0) and (1, 1, 1) = would have the corners:

=20=20

(0,0,0) (0,0,1) (0,1,1) (0,1,0) (1,0,0) (1,0,1) (1,1,1) (1,1,0)=20

Note that I am not interested in specifying topological relations (edges= ) between the corner points. I just want to represent the rectangular solid= volume bounded by these corners.

=20If you're the first to figure it out, edit this page with a solution (or= attach a comment). If you're prevented from editing this page, email = me. The first valid solution wins my heartfelt respect and admiration. = You may also win some empty flattery.

=20We will keep your solution on this wiki page to help future pioneers gra= pple with the third dimension of 19107. If you could please express your so= lution in the manner of a short descriptive article, I'd be very grateful.<= /p>=20

The solution was not long in coming. John Herring of Oracle Corporation = (none other than one of the editors of the standard) responded with instruc= tions on how to make a cube. As such, he probably has enough fame that winn= ing this contest is an insignificant addition.

=20=20=20For those unfamiliar with ISO 19107, a cube is a polyhedral surface, 6 f= ace polygons with 4 distinct points each (5 to close with the first =3D las= t). Each face shares its 4 edges with 4 other faces (with orientation

=20

= reversed).A unit cube at the origin is (using a variant of SF4SQL WKT):

=20=20POLYHEDRAL_SURFACE ( =09=09 POLYGON(0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0), =09=09 POLYGON(1 0 0, 1 0 1, 0 0 1, 0 0 0, 1 0 0), =09=09 POLYGON(1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0), =09=09 POLYGON(0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0), =09=09 POLYGON(0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0), =09=09 POLYGON(0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1) )=20

The ISO 19107 geometry specification may be found on the OGC website. Download the spec.