[tlocoh-info] Computing hulls for ancillary data values

[Andy Lyons]

Hi Liz,

To use an ancillary value as the hull metric for sorting hulls when 
constructing isopleths, etc. you pass the following two arguments:

my_lhs <- lhs.iso.add(my_lhs, sort.metric="anv", anv="humidity")

The value of the anv argument should be the name of a column in the 
attached data frame for the points. In other words, you need to bring in 
the speed values into the LoCoH-lhs object before you can use them for 
sorting hulls. There are a couple of ways to do this. If you have your 
original locations saved in a data frame or matrix, you can specify 
which additional columns to retain as ancillary values when you first 
create the locoh-xy object. These extra columns will then be carried 
over when you create the hulls (and thus be available for sorting 
purposes). This is probably the safest way to include ancillary values 
into a hullset.

There also functions lhs.anv.add() and lxy.anv.add(), which will allow 
you to import a column of values into an existing hullset or lxy object. 
These should be used with caution, however, because the function 
presumes the values being imported are in the same order as the points 
in the locoh-xy or locoh-hullset object. There is no option to match up 
points and values on a common field (although this would be helpful). If 
any duplicate points were deleted when the locoh-xy object was created, 
or reordered, then the points and values won't match up.

Other functions that work with hull metrics operate similarly (you 
specify "anv" as the hull metric, and then pass the name of the column 
as the value of a separate *anv* argument. Klunky I know). I don't know 
if that answers your question, but if you are still getting error 
messages feel free to send me some output of your console and I'll take 
a look at it.

Cheers,
Andy


On 10/6/2016 10:57 AM, Elizabeth Morata wrote:
> Hello,
>
> I am using the T-LoCoH package, along with the enjoyably written 
> tutorial to examine peregrine falcon home ranges in the Pacific 
> Northwest, and I am running into some trouble when trying to examine 
> hull metrics using ancillary speed data to create a behavioral map of 
> where birds are traveling and perhaps hunting within their home range. 
> When I create an kxy object I have been specifying the 'anv' argument 
> within the command to a data frame containing that single variable 
> extracted from the original uploaded data. Is this correct? Later on 
> when I try to compute hell metrics based on speed using the 
> 'lhs.anv.add' and then the 'lhs.filter.anv' command I receive this error:
>
> Error in lhs.filter.anv(SamoaF_ann.lhs.12000, anv.var = Speed) :
>
> and after the colon proceeds to list out each of the values contained 
> within the Speed variable. I assume I am mis-specifying some argument 
> or leaving out an important argument, has anyone else created hulls 
> based on ancillary data other than ellipse eccentricity, NSV and MNLV ?
>
> Thank you for any suggestions/input!
>
> Sincerely,
> Liz Morata
>
> -- 
> *Elizabeth-Noelle F. Morata*
> M.Sc Candidate
> Department of Wildlife
> Humboldt State University
> Arcata, CA 95521
> (510) 343-4346
> liz.morata at gmail.com <mailto:liz.morata at gmail.com>
>
>
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