[R-sig-Geo] Creating density heatmaps for geographical data

Karl Ove Hufthammer karl at huftis.org
Tue Oct 19 12:58:19 CEST 2010

Rolf Turner wrote:

>> 'ppp' objects used by 'spatstat' have an annoying structure
> <SNIP>
> Annoyance is in the mind of the beholder I think.  Personally I
> find the structure of ppp objects absolutely *delightful*! :-)
> Also, they are simple, intuitive, easy to work with, and easy to
> understand, take apart, dissect, and manipulate.  Furthermore the
> tools in spatstat make it easy to do unto ppp objects pretty well
> anything one might want to do to a point pattern.  (I'm not being
> immodest here; the tools are mainly down to Adrian.)
> Just what do you find ``annoying'' about the structure of ppp objects?

Well, I guess only the fact that they’re not ‘sp’ objects, really. And
that’s very annoying … :)

And though the ‘window’ element of ‘ppp’ objects may be of use to some 
people, I haven’t had any use for it. The annoying thing here is that the 
constructor doesn’t generate the window automatically, based on the extent / 
bounding box of the data, and don’t have an *option* for doing this, either.
Whenever I have used ‘spatstat’ (not too often), I have had to spend too 
much time looking up how the window should be specified. Having [0,1] × 
[0,1] as the *default* window, and excluding any points outside this does 
seems like a strange design decision.

Karl Ove Hufthammer

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