CODEWITHSUNDEEP
matlabmatrixlabelpoints
Mac.
Mac.

Reputation: 303

How to label points?

I try to label 70 points (which can be seen as nodes) whose coordinates are contained in a matrix with two columns. In labelize I mean to appropriate to each one a number and for example to obtain a matrix with three columns where the first two are always the coordinates and the third the label

I saw in the doc labelnode and graph for example but I do not have the right version of matlab for these functions (I use R2015a). And labelmatrix or bwlabel transforms my matrix of coordinates into a matrix of 1.

How can I do ?

317 948
319 935
320 969
320 969
326 916

Upvotes: 0

Views: 454

Answers (2)

Zizy Archer
Zizy Archer

Reputation: 1390

There are many ways to do this.

  1. Simply use numeric array with numeric labels. You can easily append this to existing table.

    arr(:,3) = labels;

  2. You can use cell array, 1 and 2 would be numbers and 3 would be then string for label.

    arrWL = cell(size(arr,1), 3);
arrWL{:,1:2} = arr;
arrWL{:,3} = labels;

  3. You can also use table to label rows and columns.

    X = arr(:,1);
Y = arr(:,2);
arrWL = table(X, Y, 'RowNames', labels);

  4. Put both data and labels together as separate entries in a cell array (with 2 elements).

    arrWL = {arr, labels};

I could probably think of some other options if none of these are suitable.

Now, to generate unique numbers for labels, use:

[~,~,positions] = unique(arr, 'rows', 'stable'); 
% I prefer stable so the first point gets index 1 etc.

Upvotes: 1

UJIN
UJIN

Reputation: 1758

I am not entirely sure if I got your problem right. For what I understood, you can simply add a column of unique numbers to your data. If we say your data is stored in matrix X, you can do:

labels = 1:size(X,1); % generate a vector of integers from 1 to number of rows of X
X = [X, labels']; % concatenate the matrix X and the vector of labels

% X = [ 317 948 1
%       319 935 2
%       320 969 3
%       320 969 4
%       326 916 5
%       .........]

If instead you want the same label for points with the same coordinates, you can use unique to generate those labels:

[~, ~, labels] = unique(X, 'rows');
X = [X, labels];


% X = [ 317 948 1
%       319 935 2
%       320 969 3
%       320 969 3
%       326 916 4
%       .........]

Upvotes: 1

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