Adjacency vs. Connectivity

Is is the same when talking about "Adjaceny" and "Connectivity"? Or, they are totally different terms?

Thanks.

[David Young]

I don't know whether my answer to your earlier question about adjacency and connectivity in images was helpful to you, so I don't know whether to reply.

Answer 1

[Walter Roberson]

An adjacency matrix is usually a binary matrix with a 1 indicating that the two vertices have an edge between them. A connectivity matrix is usually a list of which vertex numbers have an edge between them. Adjacency matrixes are easier to compute certain kinds of algorithms over, but may require more storage than a connectivity matrix (especially if the vertex degrees are low.)

Either kind of matrix can be modified to have weight (cost) information instead of just "there is a vertex" information.

[David Young]

I suspect, in the light of earlier questions, that Mr Abder-Rahman is asking about images rather than graphs.

Answer 2

[Sean de Wolski]

It depends on what you're talking about; but probably no. Adjacent objects are connected in spatial dimension but not as an object. Connected pixels (or voxels) are part of the same object and touching via connectivity.