English: per http://portlandflag.org/flag/ (view link for full description):

"The Portland Flag Association’s flag is designed to suggest both the Portland City Flag (not only to identify the Association’s home city, but to commemorate the flag’s designer Douglas Lynch and the achievement of Lynch and the Association in convincing the city government to adopt Lynch’s intended design) and the flag of NAVA (the North American Vexillological Association, in which many Association members are active). It adopts the colors and a fimbriated V-shaped element from the Portland City Flag, and the bold V-for-Vexillology (the study of flags) symbolism of the NAVA flag.

The design was originally created in 2007 by Scott Mainwaring, following the Good Flag, Bad Flag guidelines created by Ted Kaye. David Ferriday proposed modifying the original design by switching the blue and the green so as to suggest the blue sky and the green land, and the modified design was adopted through a series of deliberations and preference polls by Association as a whole in 2009-2010 (see the Vexilloid Tabloid #25, March 2010)."