[tlocoh-info] tlocoh area covered and metrics

Laurie Baker Laurie.Baker at Dal.Ca
Sun Apr 13 16:00:55 CEST 2014

Hello List,

I am using T-LoCoH to study the area surveyed by grey seals carrying acoustic tags and am interested in looking at this effort in space and time. I am looking at individual effort and also the area covered by multiple seals at the same time. 

My questions are two-fold: 
1. How to extract the total area and hull area for these tracks?

2. How you might be able to illustrate and quantify the area overlapped by individual seals in space, and in time (i.e. area covered by seals at the same time) using this tool?

Question 1:

I think I have identified where I can find this information from the object generated in the toni example, toni.lhs.k15:

#[1] "id"        "pts"       "anv"       "rw.params" "mode"      "k"         "r"        
#[8] "a"         "auto.a"    "s"         "kmin"      "dups"      "desc"      "hulls"    
#[15] "hm"        "enc.pts"   "hm.params" "gen.date"  "isos"

Is the information stored in "hulls" or "isos"?  Is there a way to extract this information one hull at a time? The command toni.lhs.k15[[1]]$hulls floods the console and I am not able to view it in its entirety.

Question 2:

I tried analyzing all tracks and not including seal id to distinguish different tracks, but this is a problem given that certain time stamps are the same. Is there a way to overlay the area covered by individuals and match this to time?



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