Can I use pixel density file to calculate habitat area

[Carolyn Devens]

Hi! I'm hoping someone can help me brainstorm. I have been trying to figure out a way that I can take my pixel density results into GIS and from that calculate the area (km2) of suitable habitat. Ideally, I'd like to take the estimated density that spacecap gave me and calculated area of habitat to determine the actually number of my species within my study range.

I'm definitely not as well versed in GIS (I'm using QGIS currently) as I'd like to be.. But I'm thinking that there has got to be a way to take the pixel densities data and perhaps apply a threshold to categorize what I deem suitable and not suitable habitat.

If anyone out there has any ideas for be if be so appreciative!
THANKS!!!

[Arjun Gopalaswamy]

Hi Carolyn:

The problem you describe below seems to be a case of working backwards in
determining what is suitable habitat. Generally, you would like to a priori
define what is suitable or unsuitable habitat (1s and 0s in the state space
of SPACECAP). And if you additionally want to incorporate covariates on
pixels, then I am afraid you will not be able to do it on SPACECAP. But it
is implemented in Royle et al. (2013) paper "Integrating resource selection
information with spatial capture-recapture" that is implemented in SCRbayes.

If you want to work backwards as you propose below, then it is only helpful
in the context of hypothesis generation but not as a way of formal
scientific inference. You can readily use the pixel specific density
estimates of SPACECAP and apply whatever threshold you deem as fit for such
hypothesis generation.


Regards
Arjun