# Plotting A Matrix Using Surfc

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Brian Peoples on 24 Apr 2019
Commented: Walter Roberson on 25 Apr 2019
Hello--
I am struggling an recieivng an error when I try to plot a matrix using surfc (in a function). I was wondering if anybody knew why.
My input for N is 10.
function lake = MakeLake_BDP(N)
lake = zeros(N,N);
lake(1,:) = -999;
lake(N,:) = -999;
lake(:,1) = -999;
lake(:,N) = -999;
%randn where the dist has a mean of 4 and sd of 2
lake(2:N-1,2:N-1) = 4 + 2.*randn(N-2);
T = lake;
w = .175; %weighing factor
for k = 1:15
T(1,:,k+1) = -999;
T(N,:,k+1) = -999;
T(:,1,k+1) = -999;
T(:,N,k+1) = -999;
for i = 2:N-1
for j = 2:N-1
[open] = Isopen(i,j,N);
M = sum(open);
T(i,j,k+1) = T(i,j,k)*(1-w)+w/M*([T(i-1,j,k),T(i+1,j,k),T(i,j-1,k),T(i,j+1,k)]*open);
end
end
end
lake = T; %sets lake equal to T
%plotting
surfc(lake);
end
function [open] = Isopen(row,col,N)
%initialize open
open = ones(4,1);
%row and col values/concention for directions
%if statement
if row == 2
open(1,1) = 0; %up
elseif row == N-1
open(2,1) = 0; %down
elseif col == 2
open(3,1) = 0; %left
elseif col == N-1
open(4,1) = 0; %right
end
end

Walter Roberson on 25 Apr 2019
Your T is created as 3 dimensional. You are trying to surfc() a 3D volume. surfc() and surf() are only for 2D arrays (on a plane that might be warped.)
You can use isosurface() or you can use slice(). Or you can use the volumeViewer() app. Or you can use vol3d v2 from the File Exchange.
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Walter Roberson on 25 Apr 2019
I am certain that you cannot use surfc() to plot all of T in one call.
What I do not know is what relationship T has to the surface of a lake.
For example I could hypothesize that T(:,:,end) might represent the surface of a lake, and that you might surfc() that .