[R-sig-eco] Types of BRB (ID and RD)

[Nick van Doormaal]

Dear list members,
Currently I'm using the BRB-models (provided by the wonderful package adehabitatHR) for analyzing movement patterns of humans.I'm a bit surprised that in the literature, BRB has not been applied so often. Especially the other types of calculations: Intensity Distributions (ID)and Recursion Distribution (RD).  Is there are a reason why this method hasn't been applied so often? In the vignette of adehabitatHR it seems to me that the BRB-method was considered one of the best methods so far to analyse movement patterns. 
I'm very interested in the recursive patterns of humans.  For example, in my data set, I tracked several teams with a 10-second interval. There is one team constantly walking up and down the same road. I expected that this team will show very different RD-values from the BRB, compared to other teams. However, when I compare the the percentage of values 0-30 (in BRB the lowest values indicate high intensity/recursion/utilization correct?) with the other teams, it seems that all the teams show very similar results. Now I'm wondering if that has anything to do with the parameters specified in the BRB. I believe it's related to the next parameters :radius:  the radius of the patches (in units of the relocation coordinates) used in the calculation of the residence time or the number of visits. If NULL, the radius is set to 3*hmin.maxt: maximum time threshold (in seconds) that the animal is allowed to spend outside the patch before that we consider that the animal actually left the patch.
In my script, I didn't set any radius (so 3*hmin, in my case 3*25m), and maxt was set to 20 seconds. The output is estimated in a 50x50m grid. See following code:
Team.rd <- BRB(Team.ltraj, D = Team.vv, Tmax = 60, tau = 5, Lmin = 0, hmin=25, grid = Team.grid, type=("RD"), same4all=FALSE, maxt = 20)
I was hoping if someone could give me some more information on what the output of the BRB actually means and if these parameters make sense or not.If someone has been using the types ID or RD, I would like to know more about their research too!
Thank you for your time! 		 	   		  
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