Hello,
You may prefer to write your own code for calculating the patch, but
I thought I would just mention that this functionality is implemented
in Caret (http://brainmap.wustl.edu/resources/caretnew.html). Caret
can read FreeSurfer surfaces. It will calculate the distance of all
nodes from a gi
The sphere-based patch will change size and shape a little when you map
it back to the folded surface due to metric distortion. So you could
refine it some, eg, run your Dijstra algorithm on just the patch. I
would not expect the distortion to make much of a difference, so it's
probably not worth
Hi Bruce
Yes, I'm sorry I wasn't clear in my previous posting. I think that you and
I are talking about the same thing...
The surface distance along the sphere from my vertex point... let's call
that arc length. So I want to have all freesurfer points which are less
than or equal to an arc leng
Hi Daniel,
don't use Euclidean distance. Use the length of the great circle
connecting each point to the central vertex on the ?h.sphere surface.
Bruce
On
Tue, 8 Mar 2005, Daniel Goldenholz wrote:
Doug
I was thinking of trying something like that.
If I took all vertices which are a radius M or
Doug
I was thinking of trying something like that.
If I took all vertices which are a radius M or less from my centriod,
aren't I basically done?
(M is defined as the maximum euclidean distance between the centroid on
the sphere and the ring of outer vertices. If my surface distance max is
calle
Hi Daniel -
Well it seems to me that you're almost there already. A Dijkstra algorithm is
the ideal engine to determine radial paths from a central node - I suspect
you just need to tune the graph cost function to take the Euclidean distance
between nodes (as opposed to the logical distance) in
You might try starting off with the ?h.sphere. It's easy to parameterize
these things on the sphere. The sphere, of course, has some metric
distortion, but if the patch is small, it might not be to bad. Once
you've identified the vertices in the patch (or maybe a slightly bigger
patch), then you c
Hi. I have a graph theory question:
I would like to make a definition of a particular patch of cortex, that
has a centroid at position (x,y,z) and has a total area of A.
I thought that this was going to be somewhat hard, but I soon learned that
it is very hard.
First, I found some code for the
