Re: [R-sig-Geo] Strange lines when projecting a world map

2013-12-07 Thread Roger Bivand
On Fri, 6 Dec 2013, Francesco Carotenuto wrote: Roger you are right, my explanation is still a bit confusing. Keeping apart the automatic procedure, that is not so much important now, the real problem, as you said, is only aesthetic. When the dataset is worldwide distributed, I don't need to

Re: [R-sig-Geo] Strange lines when projecting a world map

2013-12-07 Thread Francesco Carotenuto
Well, when one asks to a master... Then, I can write some lines to automatically select only the regions hosting the data points, keeping out useless territories.Thanks so much for the help and the patience.   Dr. Francesco Carotenuto (Ph.D.) Department of Earth Sciences Federico II University

[R-sig-Geo] Strange lines when projecting a world map

2013-12-05 Thread Francesco Carotenuto
Dear list, as in the title, I found that when projecting a world map by mollweide projection and setting a  longitude value, some strange parallels are drawn. The real problem is that these lines “interact” with a raster when performing the “over” function. How can I manage it? Here I

Re: [R-sig-Geo] Strange lines when projecting a world map

2013-12-05 Thread Roger Bivand
On Thu, 5 Dec 2013, Francesco Carotenuto wrote: Dear list, as in the title, I found that when projecting a world map by mollweide projection and setting a?? longitude value, some strange parallels are drawn. The real problem is that these lines ???interact??? with a raster when performing the

Re: [R-sig-Geo] Strange lines when projecting a world map

2013-12-05 Thread Francesco Carotenuto
Thank you for the answer. The object is the prediction location in an interpolation process. The function of overlay is involved in an automatic process and the longitude (and the kind of projection too) can change according to the dataset that is, in some cases, worldwide distributed.   Dr.

Re: [R-sig-Geo] Strange lines when projecting a world map

2013-12-05 Thread Roger Bivand
On Thu, 5 Dec 2013, Francesco Carotenuto wrote: Thank you for the answer. The object is the prediction location in an interpolation process. The function of overlay is involved in an automatic process and the longitude (and the kind of projection too) can change according to the dataset that