[R-sig-Geo] `kest` radius limits?

[Nick Eubank]

OH! I apologize. Just got the copy of your ebook and now I understand -- I
had mis-understood the nature of the border correction. Squared away now.
Thanks again!

On Wed, Jul 27, 2016 at 11:10 AM Nick Eubank <nickeubank at gmail.com> wrote:

> Thanks Adrian. I think my confusion is that there are lots of points that
> are more than r units away.
>
> Sweden is basically a tall, thin rectangle. It's ~260km wide at its
> narrowest point, but it's 1400km tall. And my point density is pretty high,
> so for any point, there are lots of other points at more than 160km (just
> not in all directions). In other words, the maximum distance from any
> point to the boundary is NOT 160km. Thus my confusion.
>
> Also, I've been overriding the `xlim` too -- the x-axis of the plot window
> runs all the way to the value I want (300km), and the null poisson model
> runs to 300km, it's just the estimates of k(r) that stop.
>
> I don't think I can send pics to the r-geos list, but I'll email the image
> to you.
>
> (Ordered your book, btw)
>
>
>
> On Wed, Jul 27, 2016 at 3:36 AM Adrian Baddeley <
> adrian.baddeley at curtin.edu.au> wrote:
>
>> Nick Eubank writes:
>>
>> > I'm running kest on points in Sweden (which is about 200km wide at its
>> > narrowest) with 'border' correction and lots and lots of points.
>>
>> > However, I can't get estimates of K(r) for radii beyond ~160km. I bumped
>> > `rmax`, and if I plot my results, the null model line extends  to the
>> > `rmax` value, but the K(r) estimates just stop at ~160km.
>>
>> For the border correction, the estimate of K(r) becomes NA (and is not
>> plotted) as soon as there are no data points that lie more than 'r' units
>> away from the boundary. If the maximum distance from any data point to the
>> boundary of Sweden is 160 km, then this is the behaviour I would expect.
>>
>> All explained in chapter 7 of the spatstat book.
>>
>> If you print a summary function object, the output shows the "recommended
>> range" of distance values and the full "available range". By default,
>> the plots of summary functions use the "recommended range" of distance
>> values rather than the full "available range". To override this, when you
>> plot the summary function, use 'xlim' to control the range of 'r' values.
>> (xlim should be an argument in the 'plot' call).
>>
>> Adrian Baddeley
>>
>>
>>

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