Hi Adrian, One followup I can't find answered in the book -- is there an analogue to the isotropic edge correction in kest.fft? Or does it only do border?
Thanks! Nick On Wed, Jul 27, 2016 at 10:58 AM Nick Eubank <nickeub...@gmail.com> wrote: > Great, thanks so much for taking the time to answer this Adrian! And for > the book link! > > On Wed, Jul 27, 2016 at 3:25 AM Adrian Baddeley < > adrian.badde...@curtin.edu.au> wrote: > >> Nick Eubank writes: >> >> >> > Using `kest` to estimate a ripley's K for a country. >> >> This is a question about the 'spatstat' package. >> The function name is 'Kest'. >> >> > The authors of the package suggest isotropic is best when >> computationally tractable for >> > irregular shapes, but I noticed in Ripley (1988) that this correction is >> > only "unbiased provided E is convex", where E is the boundaries of >> study. >> >> This is covered at length in Chapter 7 of the 'spatstat book' >> < >> https://www.crcpress.com/Spatial-Point-Patterns-Methodology-and-Applications-with-R/Baddeley-Rubak-Turner/p/book/9781482210200 >> >> The isotropic corrected estimate is unbiased for all r < R, where R is >> the radius of the smallest circle that encloses the entire window (assuming >> the window is connected). >> >> > With that said, the picture in Ripley (1988) illustrating this >> correction >> > is NOT convex (it's a kidney shape). >> >> So the statement above applies to this window. >> >> > I know this isn't quite an "r-implementation" question, but: anyone >> know if >> > isotropic correction is unbiased for an odd shape like a country-outline >> > (in this case Sweden)? Or should i use the `border` correction? >> >> Use the isotropic correction. >> >> >> Adrian Baddeley >> >> >> >> [[alternative HTML version deleted]] _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
