Use of the "zone area" to obtain landscape size in the IIC calculation.

Memo

Hello. My name is Guillermo Dávila, a PhD student in Ecology and a member of NERF (Núcleo de Ecología de Rodovias e Ferrovias) at UFRGS in Brazil. I am currently working on connectivity in my doctoral project.
I noticed that the Graphab software uses the area of the "zone" (height * width) to calculate metrics like the IIC and not the area of the study polygon. This is a problem when our study area is irregular and therefore the total landscape area does not correspond to its zone.

If this is the case, there is no way to contour this directly in Graphab, right ?
Could you confirm my suspicions? (to manually adjusting the IIC Global calculations)
I'm unsure if this affects d_IIC. It shouldn't affect the order of importance in the topological map, right? But changing the net value?

gvuidel

Hi,
You're right, the PC and IIC metrics are divided by the total rectangular landscape area. If your zone is not rectangular, you have to manually adjust the metric value.
The delta metrics dPC and dIIC are not affected by the area of the zone. The area in denominator cancel out :
(x/A - x'/A) / (x/A) = (x - x') / x

Memo

Obrigado!