[R-sig-Geo] Spatial auto-correlation globally (sphere)

[Alex Mandel]

Thanks it looks like cshapes might be exactly what I was looking for and
more. I thought I knew what most of the Spatial packages were for,
clearly there are still a few more to wander through. It's odd that the
Task View pages don't have the same short description lines next to
packages the way the normal package list on the website does.

I think I was leaning towards polygons, I wasn't sure since the wrapping
of the dateline was the bigger problem to solve in my mind.
Cshapes has an interesting way of doing that where they look for the
nearest 2 nodes that make up the borders rather than directly testing
polygons or line edges. So it's really all points then.

The reason for the package is actually quite similar what I planned to
do with it so that paper you linked is very useful.

Thanks,
Alex


On 03/23/2014 02:41 PM, Roger Bivand wrote:
> On Sun, 23 Mar 2014, Alex Mandel wrote:
> 
>> Has anyone seen a method for creating a neighbor list, for use in
>> spatial auto-correlation tests, that treats the earth as a sphere so
>> that relationships can go shortest distance. I'm trying to make a
>> neighbor list of all countries in the world.
> 
> Please start by specifying the support you intend to use (centroid point
> support, polygonal support, what?). If point support, setting
> longlat=TRUE in dnearneigh() in spdep with a matrix of coordinates, or
> using an object inheriting from SpatialPoints with the appropriate CRS
> will give you Great Circle distances; polygons are more complicated.
> Have you looked at the cshapes package, also mentioned in the Spatial
> Task View, which appears to do what you want to do? It has an R Journal
> article:
> 
> http://journal.r-project.org/archive/2010-1/RJournal_2010-1_Weidmann+Skrede~Gleditsch.pdf
> 
> 
> Roger
> 
>>
>> Yes I realize that the relatedness may not be distance and I might
>> weight on some other factor but I need the neighbor list to start.
>>
>> Example, US <-> Japan, China or Russia should be a line across the
>> Pacific
>>
>> Perhaps I need to develop the neighbor list using some sort of social
>> diagramming tool instead.
>>
>> Any leads would be appreciated.
>>
>> Thanks,
>> Alex
>>
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>