Boundary shape

[Rich Shepard]

On Sat, 10 Jul 1999, William L. Baker wrote:

> Most shape indices (including perimeter/area) are measuring boundary
> complexity to some extent, but are more a measure of compactness. 
> Perimeter/area has the undesirable trait of varying with the size of the
> polygon even if polygon shape remains constant, so it's not a good measure
> of compactness/boundary complexity if polygons vary in size. A better
> measure is either the corrected perim./area index or the related
> circumscribing circle index.  Both are in the r.le programs which work
> with GRASS.

Bill,

  You're absolutely correct. That's why I snuck in the bit about doing your
own interpretation and calibration. Most simple indices of real ecosystems
fail miserably. Let me rephrease that: they all fail miserably. But, they
provide single numbers which are often attractive to regulators regardless
of whether or not the number has any real meaning. :-)

Ciao,

Rich

Dr. Richard B. Shepard, President
Applied Ecosystem Services, Inc.
2404 SW 22nd Street
Troutdale, OR 97060-1247  U.S.A.
+ 1 503-667-4517 (voice) | + 1 503-667-8863 (fax)
rshepard at appl-ecosys.com
           Making environmentally-responsible mining happen.