Hello, I have a couple of question regarding object owin in spatstat package. I am going to simulating a spatial point process over a collection of contiguous regions (e.g. regions with some common borders). Firstly I am going to simulate a poisson process conditionally to a fixed number of events (runifpoint) but later I could need to simulate process that deviate from CSR; my basic aim is getting the number of points in each regions. I read that in spatstat it is not possible creating owin objects where polygons share borders. I wonder if it could be reasonable creating several owin objects (one for each region) and simulating a spatial point pattern over the union of them. If so, I guess there will be no problem about the homogeneous case but my first point is about the inhomogeneous one: might be possible simulate an inhomogeneous poisson point process in such as union.owin window? The second and final question regards a problem about self-intersection. When I try to create an owin objects lot of my region (in this case the number 6) meet the following problem: w6 <- owin(poly = emr.poly[[6]]) Polygon is self-intersecting Error in owin(poly = emr.poly[[6]]) : Polygon data contain self-intersection
Bear in mind that I do not have any shape file of my collection of regions, just x-y coordinates obtained by exporting the map from winbugs by using "export Splus". Thus for many regions I can not obtain an owin object because of self-intersection, and as a result I can not obtain the union of owin objects I am interested in. I have to say I am not interested in a fine specification of borders, so I wonder if there is an easy way to eliminate point coordinates responsible for self-intersection. Do you have any suggestion please? Thank you very much in advance Massimo _______________________________________________ R-sig-Geo mailing list [email protected] https://stat.ethz.ch/mailman/listinfo/r-sig-geo
