COG, Center of Gravity

This document shortly describes COG, a Center of Gravity programme for BNA files 
programmed by Jrgen Grieser, FAO/NRC (agromet@fao.org) January, 2007.

Purpose:
COG reads polygons which represent areas on Earth (eg. Boundaries of countries, 
provinces, districts, etc.) and estimates the area and the center of gravity (centroid) of 
these polygons. 

Output:
For the input file NAME.bna COG produces 3 outputs:
NAMECentroid.bna contains the centroids for all polygons in NAME.bna,
NAMEArea.csv contains the area in square kilometers for each polygon in NAME.bna 
and NAMEMap.bmp contains the map of the polygons and centroids as bitmap.

Setup:
COG comes as a zipped file containing the executable COG.exe plus the MS Windows 
common dialogue as an activeX component, necessary to run it on some configurations. 

In order to run COG just extract the zipped file into a directory and run COG.exe.
Some example BNA files are provided.

Constraints:
The first and the last point of each polygon must be identical!
The polygons must not be self intersecting!
The polygons must not have any holes!

Warranty and Disclaimer:
FAO declines all responsibility for errors or deficiencies in the software or in the 
documentation accompanying it, for program maintenance and upgrading as well as for 
any damage that may arise from them. FAO also assumes no responsibility for errors and 
omissions in the data provided. Users are, however, kindly asked to report any errors or 
deficiencies in this product to FAO.

All rights reserved. Reproduction and dissemination of material in this information 
product for educational or other non-commercial purposes are authorized without any 
prior written permission from the copyright holders provided the source is fully 
acknowledged. Reproduction of material in this information product for resale or other 
commercial purposes is prohibited without written permission of the copyright holders. 
Applications for such permission should be addressed to the Chief, Publishing 
Management Service, Information Division, FAO, Viale delle Terme di Caracalla, 00153 
Rome, Italy or by e-mail to copyright@fao.org.  FAO 2007
