[R-sig-Geo] Point pattern add covariates

[Edzer Pebesma]

On 07/24/2012 09:00 AM, Barry Rowlingson wrote:
> On Tue, Jul 24, 2012 at 3:53 AM, Adrian.Baddeley at csiro.au
> <Adrian.Baddeley at csiro.au> wrote:
> 
>> I don't know why Barry Rowlingson is giving you advice about spatstat - he recently said no-one should be using spatstat anyway - maybe it's all part of a disinformation campaign!
> 
>  ??!??!!
> 
>  The original post didn't mention spatstat and neither did I!
> 
>  And I don't recall saying flat out that no-one should use spatstat.
> Everyone doing spatial point pattern analysis should be using
> spatstat, and *not* using splancs - I don't think there's anything
> (useful) that splancs does that spatstat doesn't do. If there is, then
> I suggest sometime we sort out a google summer of code project
> sometime to kill off splancs and graft anything useful into spatstat
> (hmmm didnt we try that ten years ago? :))
> 
>  However I don't like the duplication of spatial data handling and
> manipulation between packages such as spatstat and sp. We have some
> very nice raster and vector data types now, and if spatstat could use
> them (natively without coercion) it would save a lot of unneccessary
> duplication. In one of the packages I'm involved in it seems that
> we're constantly converting from sp to ppp and back again in order to
> get some functionality from a package that only handles one!
> 
>  So I might have said 'Don't do X in spatstat', but I certainly didn't
> say 'Don't do K, F, or G in spatstat'. I more likely said 'Don't do K
> in splancs - do it in spatstat!'

I can only recall (but can't trace back) that Barry mentioned recently
that the spatstat objects do not handle coordinate reference systems.

The objects in sp are not tailored in particular for point pattern
analysis (and neither for geostatistics) -- SpatialPoints objects for
instance do not hold an observation window, which would be indispensible
to compute a point density.

The classes in sp do contain, I believe, the building blocks needed for
spatstat objects, and one could easily subclass SpatialPoints for a
SpatialPointsPattern (containing an observation window), and a
SpatialPointsDataFrame to form a marked point pattern with observation
window.

By doing this, seemingly trivial mistakes could be caught, e.g. false
matching of points, windows, or marks by ignoring coordinate reference
systems, or doing Euclidian distances from long/lat coordinates. Seeing
this as a benefit of course assumes that (the spatstat) code developers
*want* to catch such errors.

It would be good to also hear some response from spatstat users whether
a tighter integration between spatstat and sp would be appreciated, or not.
-- 
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of Münster
Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251
8333081, Fax: +49 251 8339763  http://ifgi.uni-muenster.de
http://www.52north.org/geostatistics      e.pebesma at wwu.de