[GRASS-user] meaning of "geometry"

[Rich Shepard]

On Tue, 25 Oct 2016, Dave Roberts wrote:

> So now when I see "geometry" in a manual page or GRASS-user posting I
> interpret that to mean "vertices, nodes, centroids, and associated
> categories ordered by the (not necessarily consecutive) layer numbers" as
> that's the essential nature of a record in the coor file that manages all
> this.

> Obviously that's more operational than conceptual so I was wondering where 
> the concept of geometry is actually defined.

Dave,

   If I may contribute a thought or two to this thread: there are two
definitions of 'geometry' which we all use. One definition is coordinate
geometry which can be described as where points on a geographic surface are
located; the x, y values.

   Then there's object geometry. When setting a dinner table it's common to
place plates, glasses, and flatware in designated positions relative to each
other. Same with the controls in a vehicle: the accelerator is on the right,
the brake in the center and the clutch on the left (at least here in the
US; it's been decades since I drove in the UK).

   If we think of GRASS' geometry as object geometry, the placement of vector
objects relative to each other it might lessen any confusion.

Rich