Resampling a set of 2D Points to a certain value

Hi,

I have set of 2D Points in a matrix.Lets assume,that its size is around 30. I would like to resample it to around 55 points,with no duplication of points as well as retaining the initial coordinates.

I would be really glad,if someone can let me know regarding this.

Answer 1

[KSSV]

Let x and y be your 2D points which are 30 in number.

xi = linspace(min(x),max(x),50) ;
yi = interp1(x,y,xi) ;
iwant  = [xi yi]

[Math Enthusiast]

But I have one more issue. What if my dataset does not contain unique points. Then I get an error saying "The grid vectors must contain unique points"

My data set is as follows:

0.473856000000000  0.815359000000000
0.478758000000000  0.816993000000000
0.482026000000000  0.818627000000000
0.488562000000000  0.820261000000000
0.495098000000000  0.821895000000000
0.511438000000000  0.823529000000000
0.517974000000000  0.823529000000000
0.526144000000000  0.823529000000000
0.531046000000000  0.823529000000000
0.540850000000000  0.823529000000000
0.580065000000000  0.820261000000000
0.591503000000000  0.818627000000000
0.602941000000000  0.816993000000000
0.609477000000000  0.815359000000000
0.627451000000000  0.812092000000000
0.647059000000000  0.807190000000000
0.663399000000000  0.803922000000000
0.681373000000000  0.795752000000000
0.692810000000000  0.790850000000000
0.712418000000000  0.784314000000000
0.728758000000000  0.776144000000000
0.743464000000000  0.771242000000000
0.754902000000000  0.763072000000000
0.766340000000000  0.754902000000000
0.785948000000000  0.743464000000000
0.803922000000000  0.730392000000000
0.816993000000000  0.723856000000000
0.838235000000000  0.710784000000000
0.859477000000000  0.694444000000000
0.882353000000000  0.676471000000000
0.898693000000000  0.661765000000000
0.908497000000000  0.651961000000000
0.921569000000000  0.633987000000000
0.933007000000000  0.614379000000000
0.950980000000000  0.584967000000000
0.955882000000000  0.576797000000000
0.962418000000000  0.563725000000000
0.968954000000000  0.550654000000000
0.972222000000000  0.539216000000000
0.980392000000000  0.504902000000000
0.985294000000000  0.490196000000000
0.990196000000000  0.472222000000000
0.995098000000000  0.462418000000000
0.996732000000000  0.447712000000000
1  0.426471000000000
1  0.410131000000000
1  0.398693000000000
1  0.383987000000000
0.998366000000000  0.367647000000000
0.995098000000000  0.352941000000000
0.993464000000000  0.343137000000000
0.993464000000000  0.338235000000000
0.986928000000000  0.318627000000000
0.985294000000000  0.308824000000000
0.977124000000000  0.287582000000000
0.973856000000000  0.276144000000000
0.968954000000000  0.264706000000000
0.964052000000000  0.254902000000000
0.952614000000000  0.236928000000000
0.941176000000000  0.212418000000000
0.933007000000000  0.199346000000000
0.916667000000000  0.178105000000000
0.903595000000000  0.160131000000000
0.895425000000000  0.150327000000000
0.872549000000000  0.125817000000000
0.864379000000000  0.116013000000000
0.852941000000000  0.104575000000000
0.839869000000000  0.0947712000000000
0.820261000000000  0.0816993000000000
0.800654000000000  0.0653595000000000
0.781046000000000  0.0539216000000000
0.764706000000000  0.0506536000000000
0.736928000000000  0.0375817000000000
0.704248000000000  0.0261438000000000
0.683007000000000  0.0179739000000000
0.668301000000000  0.0130719000000000
0.635621000000000  0.00816993000000000
0.619281000000000  0.00326797000000000
0.584967000000000  0
0.570261000000000  0
0.552288000000000  0
0.535948000000000  0
0.514706000000000  0
0.483660000000000  0
0.470588000000000  0
0.455882000000000  0.00326797000000000
0.446078000000000  0.00326797000000000
0.418301000000000  0.00653595000000000
0.377451000000000  0.00816993000000000
0.359477000000000  0.0147059000000000
0.349673000000000  0.0163399000000000
0.338235000000000  0.0196078000000000
0.333333000000000  0.0212418000000000
0.312092000000000  0.0261438000000000
0.302288000000000  0.0277778000000000
0.294118000000000  0.0294118000000000
0.281046000000000  0.0343137000000000
0.267974000000000  0.0375817000000000
0.258170000000000  0.0408497000000000
0.245098000000000  0.0473856000000000
0.233660000000000  0.0522876000000000
0.222222000000000  0.0539216000000000
0.197712000000000  0.0604575000000000
0.165033000000000  0.0718954000000000
0.133987000000000  0.0833333000000000
0.119281000000000  0.0915033000000000
0.112745000000000  0.0964052000000000
0.111111000000000  0.0996732000000000
0.0964052000000000  0.111111000000000
0.0866013000000000  0.119281000000000
0.0735294000000000  0.130719000000000
0.0669935000000000  0.147059000000000
0.0653595000000000  0.156863000000000
0.0490196000000000  0.179739000000000
0.0392157000000000  0.189542000000000
0.0343137000000000  0.200980000000000
0.0294118000000000  0.210784000000000
0.0245098000000000  0.225490000000000
0.0163399000000000  0.250000000000000
0.0147059000000000  0.258170000000000
0.0114379000000000  0.271242000000000
0.00816993000000000  0.282680000000000
0.00326797000000000  0.300654000000000
0  0.330065000000000
0  0.343137000000000
0.00163399000000000  0.364379000000000
0.00490196000000000  0.379085000000000
0.00653595000000000  0.398693000000000
0.00980392000000000  0.424837000000000
0.0114379000000000  0.437908000000000
0.0147059000000000  0.450980000000000
0.0196078000000000  0.472222000000000
0.0277778000000000  0.498366000000000
0.0343137000000000  0.517974000000000
0.0408497000000000  0.537582000000000
0.0490196000000000  0.555556000000000
0.0620915000000000  0.580065000000000
0.0718954000000000  0.602941000000000
0.0784314000000000  0.612745000000000
0.0849673000000000  0.625817000000000
0.0964052000000000  0.638889000000000
0.102941000000000  0.648693000000000
0.112745000000000  0.660131000000000
0.122549000000000  0.669935000000000
0.138889000000000  0.684641000000000
0.143791000000000  0.689542000000000
0.151961000000000  0.694444000000000
0.165033000000000  0.704248000000000
0.173203000000000  0.707516000000000
0.181373000000000  0.710784000000000
0.192810000000000  0.715686000000000
0.205882000000000  0.720588000000000
0.222222000000000  0.727124000000000
0.233660000000000  0.730392000000000
0.240196000000000  0.735294000000000
0.253268000000000  0.741830000000000
0.261438000000000  0.743464000000000
0.269608000000000  0.750000000000000
0.276144000000000  0.751634000000000
0.282680000000000  0.756536000000000
0.289216000000000  0.761438000000000
0.299020000000000  0.766340000000000
0.303922000000000  0.767974000000000
0.305556000000000  0.771242000000000
0.310458000000000  0.771242000000000
0.313725000000000  0.772876000000000
0.321895000000000  0.777778000000000
0.328431000000000  0.777778000000000
0.333333000000000  0.781046000000000
0.336601000000000  0.781046000000000
0.339869000000000  0.782680000000000
0.348039000000000  0.784314000000000
0.357843000000000  0.787582000000000
0.362745000000000  0.789216000000000
0.367647000000000  0.790850000000000
0.370915000000000  0.790850000000000
0.375817000000000  0.792484000000000
0.380719000000000  0.794118000000000
0.385621000000000  0.794118000000000
0.390523000000000  0.795752000000000
0.395425000000000  0.795752000000000
0.403595000000000  0.797386000000000
0.411765000000000  0.800654000000000
0.415033000000000  0.800654000000000
0.421569000000000  0.802288000000000
0.426471000000000  0.802288000000000
0.433007000000000  0.805556000000000
0.436275000000000  0.805556000000000
0.439542000000000  0.807190000000000
0.444444000000000  0.807190000000000
0.449346000000000  0.810458000000000
0.454248000000000  0.810458000000000
0.459150000000000  0.813725000000000
0.464052000000000  0.813725000000000
0.472222000000000  0.816993000000000
0.480392000000000  0.818627000000000
0.483660000000000  0.818627000000000
0.490196000000000  0.818627000000000
0.495098000000000  0.818627000000000
0.504902000000000  0.820261000000000
0.508170000000000  0.820261000000000

[KSSV]

Do the unique X's have unique y's? If so remove them.

[Math Enthusiast]

I modified my code like this :

[x, index] = unique(x); 
xi = linspace(min(x),max(x),70) ;
yi = interp1(x,y(index),xi) ;
iwant  = [xi yi];
scatter(xi,yi,'r');

But result looks really bad :(.

The initial and final (after interpolating look like this):

Hope you understand,what I exactly need.