How to remove open contours

I have a volume of data. At each x location, I'd like to process some contours in the y-z plane. As part of that, I'd like to only consider the closed contours. I'm trying to do this by filtering out any contours that touch the edge of the plane (they could technically be tangent, but I'm willing to risk that). Here's my code with more explanations in comments.

for i = 1:length(xinds) % looping through x locations
    yzconlev{i} = contourc(zdim,ydim,squeeze(uavgdef(xinds(i),:,:))',levs); % creating contours
    [yzczdim{i},yzcydim{i},yzcuavgdef{i}] = C2xyz(yzconlev{i}); % Using C2xyz to get interpolated 
    % grid data of each contour
    for j = 1:length(yzcuavgdef{i}) % looping through contours at each x
        coniny{i}{j} = find(yzcydim{i}{j}~=ydim(1) & yzcydim{i}{j}~=ydim(end)); % find contours
        % that touch the edge as defined by ydim
        coninz{i}{j} = find(yzczdim{i}{j}~=zdim(1) & yzczdim{i}{j}~=zdim(end)); % same, but for
        % other dimension
        if size(coniny{i}{j}) == size(yzcydim{i}{j})
            iny{i}{j} = yzcydim{i}{j};
        end
        if size(coninz{i}{j}) == size(yzczdim{i}{j})
            inz{i}{j} = yzczdim{i}{j};
        end
        if isempty(iny{i}{j}) == 0 && isempty(inz{i}{j}) == 0
            iny2{i}{j} = iny{i}{j}; % can't index with j if I want to skip some...
            inz2{i}{j} = inz{i}{j};
        end
        % would then continue processing only with closed contours       
    end
end

This is close. I get only closed contours in iny and inz, but it leaves empty cells where the open contours were, and now I need to find the intersection of the two. I have the start of a solution, but I'm struggling to figure out how to index it so it works. As is, I still get empty cells as a result of skipping some js based on the condition.

Answer 1

[Daniel]

Here's what I finally figured out. I'm certain that improvements could be made as I'm not an "efficient" coder. I welcome input.

for i = 1:length(xinds) % loop through the planes
    k = 1;
    yzconlev{i} = contourc(zdim,ydim,squeeze(uavgdef(xinds(i),:,:))',levs); % create contours
    [yzczdim{i},yzcydim{i},yzcuavgdef{i}] = C2xyz(yzconlev{i});
    for j = 1:length(yzcuavgdef{i}) % loop through the contour levels in each plane
        conin{i}{j} = find(yzcydim{i}{j}~=ydim(1) & yzcydim{i}{j}~=ydim(end)...
            & yzczdim{i}{j}~=zdim(1) & yzczdim{i}{j}~=zdim(end)); % find contours that don't touch
        % edges of domain to exlude open contours
        if size(conin{i}{j}) == size(yzcydim{i}{j})
            if size(conin{i}{j}) == size(yzczdim{i}{j})
                iny{i}{k} = yzcydim{i}{j}; % create sets of y and z coords for only open contours
                inz{i}{k} = yzczdim{i}{j};
                k = k+1;
            end
        end
    end
    for j = 1:length(iny{i})
        concenter{i}(j,:) = [mean(inz{i}{j}),mean(iny{i}{j})]; % find center of open contours
    end
    incen{i} = find(concenter{i}(:,1)<1 & concenter{i}(:,1)>-1 ...
        & concenter{i}(:,2)<1 & concenter{i}(:,2)>-1); % find centers that are within "middle"
    inconcen{i} = concenter{i}(incen{i},:); % subset of centers in "middle"
    for j = 1:length(incen{i})
        inycen{i}{j} = iny{i}{incen{i}(j)}; % subset of contours with centers in "middle"
        inzcen{i}{j} = inz{i}{incen{i}(j)};
        conradii{i}{j} = sqrt((inconcen{i}(j,1)-inzcen{i}{j}).^2+...
            (inconcen{i}(j,2)-inycen{i}{j}).^2); % R, radii of contours with centers in "middle"
        conavgradius{i}(j) = mean(conradii{i}{j}); % average radius of each contour
    end
    gt1{i} = find(conavgradius{i} >= 1); % find average radii greater than one
    radgtone{i} = conavgradius{i}(gt1{i}); % subset of average radii greater than one
    if isempty(radgtone{i}) == 1
        radgtone{i} = NaN; % need this for max to work below
    end
    avgradgtone(i) = nanmean(radgtone{i});
    medradgtone(i) = nanmedian(radgtone{i});
    maxradgtone(i) = max(radgtone{i});
    inconcengt1{i} = inconcen{i}(gt1{i},:); % subset of centers with average radii greater than one
    for j = 1:length(gt1{i})
        inycengt1{i}{j} = inycen{i}{gt1{i}(j)}; % subset of contours with average radii greater than one
        inzcengt1{i}{j} = inzcen{i}{gt1{i}(j)};
    end
end