[tlocoh-info] Reporting home ranges (wet and dry seasons combined) and seasonal home ranges

[elikana kalumanga]

Many thanks, Andy.
I will try to use k and a methods and compare the results.  
Elikana 

     On Wednesday, February 25, 2015 5:41 PM, Andy Lyons <lyons.andy at gmail.com> wrote:
   

  Hi Elikana,
 
 Thanks for your query. See my comments below, and let us know if you have any other questions. 
 
 Andy
 
 
 On 2/23/2015 6:16 PM, elikana kalumanga wrote:
  
     Hi Tlocoh users,       I have calculated the home ranges of six different animals using    HR_area<-isopleths(K.lhs)
 HR_area[[1]]@data  and got the results as shown below. a) Is it allowable to present results as I have done in Table 1? 
    
 
 I'm not sure what you mean 'allowable', but your table looks fine. Isopleth area is given in map units squared, so if your map units are meters then dividing by 10^6 gives you km2 (as you've done). A reader may want to know more what 'duplicate points' means. because two fixes at the same location are fine as long as they have different time stamps. 
 
 
   b) Is it allowable to partition the lxy object into seasons (Wet and Dry) and calculate seasonal home ranges using the same k and s values? k=15, s=0.01   
 
 When you're working with subsets of your data from the same individual, using the same parameter values (k and s) is pretty standard, and certainly defensible in terms of comparing apples to apples. This presumes that the movement pattern and sampling intervals in the wet and dry seasons are not dramatically different. If on the other hand, for example, there are many more spatial outliers in the dry season (because the animal was wondering far and yonder in search of water sources), then the same value of k that did a nice job modeling space use in the wet season could potentially result in large ispoleths in the dry season that include large areas where the animal never was (in which case you might to switch to the 'a' method which is generally more robust to different geometric distributions of points). Hence inspecting the isopleth-area curves and isopleth maps for a reality check is still worth doing, but if they are not too dissimilar then using the same parameter values would be a good choice.  
 
 
      
        Thanks you,       /Elikana       A: Calculating the home ranges (50% core and 95% HR) for K   iso.level       area edge.len  nep       ptp   hm.val num.hulls   1      0.10   70269838 108903.2  306 0.1039755  9151933        76   2      0.25  202560380 241182.6  751 0.2551818 13458959       161   3      0.50  411476203 396289.0 1478 0.5022086 17707306       296   4      0.75  795190800 498162.6 2223 0.7553517 25729873       578   5      0.95 1930117958 593033.8 2800 0.9514101 64256706      1873       Table 1: Number of fixes and estimated home ranges from the lhs                     
|   Name   |   Number of fixes (GPS points)   |   Duplicate points   |   Number of days/dates   |   Core area (km2)   (50%)   |   Home range   Km2    (95%)   |
|   K   |   2943       |   0   |   743.9    2012-08-15 2014-08-29   |   411.48km²   |   1930.1km²   |

        
 
    
 
 

   
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