[FORGED] Spatial points pattern generation
On 14/12/16 12:17, Maurizio Marchi wrote:
Hello everybody, working with the spatstat package I would need to generate some artificial spatial points pattern with an associate mark. More in detail I would like to create 3 or 4 examples with approximately 1000 trees on a square of 100x100 metres (1 hectare) with 1) Completely random distribution 2) Clustered distribution 3) Regular distribution 4) Mixed distribution all the points must have an associated mark (e.g. in case of trees a diameter in centimeters) and the autocorrelation must be detectable (the exercise is exactly aimed to study the presence of autocorrelation)
"Completely random" patterns can be generated using rpoispp().
Clustered patterns can be generated using (amongst other functions)
* rThomos()
* rMatern()
* rLGCP()
or more generally using rNeymanScott().
Regular patterns can be generated using rmh() with 'cif="strauss"'
or using rStrauss().
Not quite sure what you mean by a "Mixed distribution". Perhaps you
want to do something like generate patterns from 1), 2) and 3) and then
superimpose them into a single pattern using superimpose().
Marks are assigned to points of a pattern by means of the syntax
marks(X) <- m
where m is a vector or factor of length equal to npoints(X) or a data
frame with nrows(m) = npoints(X).
How you generate the marks is up to you.
Read the (incredibly well written :-) ) help for the functions referred
to above, or better still read the (even more incredibly well
written :-) ) book to which you can find a pointer by pointing your
browser at http://spatstat.github.io.
That's about all I can say in response to such a general question. If
you have further focussed and specific questions, please get back to me.
cheers,
Rolf Turner
Technical Editor ANZJS Department of Statistics University of Auckland Phone: +64-9-373-7599 ext. 88276