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Questions about betweennes- and eigenvector centrality

Hi everyone,
I am a marine bio grad student working on a larval dispersal model to estimate MPA connectivity and I am a complete beginner. 
I am trying to follow the method of Andrello et al. (20132017) and would like to calculate betweennes centrality (BC) and eigenvector centrality (EC) by using R packages like rgeos, igraph, and sp. 
 
My basic setup for the simulation so far involves the release of larvae from the centroid of each MPA  with a recruitment zonefile of all MPAs, including the source MPA.
 
Is that enough for calculating BC & EC and for the connectivity analysis in general?
 
I am also wondering:
1. Does it matter whether I release larvae from centroid or from zones?
 
2. What is the difference between the available scripts for computing connectivity/distance and calculating BC and EC ? Can I use the same simulation for both? 
 
3. Most of the R scripts involve a release zone. Should one always be added to the simulation or is it enough to use the zonefile only when running the scripts?
 
4. Is there an R function that can create an ichthyop zonefile from ArcGis polygons?
 
Any help is deeply appreciated,
Vivien

Ichthyop version: 
Ichthyop 3.3alpha
Hydrodynamic dataset: 
ROMS
Java version: 
Java SE 8
Operating system: 
Windows 10

Hello Vivien,

For your specific questions regarding BC and EC please contact Marco Andrello directly.

> 3. Most of the R scripts involve a release zone. Should one always be added to the simulation or is it enough to use the zonefile only when running the scripts?

It is not compulsory to have a release zone. You can use the other ways of releasing particles ("stain", "drifters") and then write your own scripts for post-processing.

> 4. Is there an R function that can create an ichthyop zonefile from ArcGis polygons?

A few years ago a student  wrote an R script that transforms shapefiles into Ichthyop zones. It is a bit old, not sure if it still works, but if you want to give it a try then send me an email I'll send you the script.

Christophe Lett

 

 

Hi Christophe,
Thank you for your response.
I  created the polygons in Ichthyop of as few points as possible and they turned out accurate enough so I think I will just use that.  
/Vivien