[Openspace] k-neighbors in GeoDA

[galvis at uiuc.edu]

Chris is right, I am not necessarily one of the closest neighbor to my
nearest neighbors. Think about this example, if you were to construct
a 4-nearest neighbors that include Hawaii, you may fin that California
is one of the closest neighbors, but for California's side, Hawaii is
not one of the 4-nearest neighbors.
On the other hand, the meaning of the "order of contiguity", refers to
how many steps separate me from my neighbors. In a regular grid,
following a queen criterion, it would be just the 8 cells surrounding
any particular cell. Second order of contiguity should then have 15
neighbors. If you think about it, you may figure out why yo didn't
have the asymmetry "problem" when creating euclidean, queen or rook
weigh matrices.

L.

On 11/22/07, Richard Ngetich <richard.ngetich at undp.org> wrote:
> Dear German
>
> Perhaps you meant to ask what is the meaning of "the order of contiguity"?
>
> Richard
>
> -----Original Message-----
> From: German Muchnik Izon [mailto:german at unm.edu]
> Sent: Wednesday, November 21, 2007 8:53 PM
> To: openspace at sal.uiuc.edu
> Subject: [Openspace] k-neighbors in GeoDA
>
> Hi,
>
> Does anyone know how GeoDA creates a weight matrix based
> on, for instance, 4 neighbors? Does it use distance to
> determine the closets four neighbors?
> I imported a 4-neighbor weight matrix I created in GeoDA
> to R but when I check for symmetry, R tells me that the
> matrix is not symmetric. I did not have this problems with
> other weight matrices I created in GeoDA (i.e. euclidean,
> queen, rook)?
> Also, when I create rook or queen continuity weight
> matrix, what is the meaning of "the order of continuity"?
>
> Thank you!
> German.
>
>
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