How to grid xyz data without interpolation

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Daniella Della-Giustina 2015-5-21

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评论： Daniella Della-Giustina 2015-5-26

I have a Digital Elevation Model (DEM) was provided as a list of x, y, z coordinates (x and y are 1 x N sized vectors). I would like to grid the so that I can view z as an N x N matrix, but I do NOT want to perform any interpolation on the surface described by z. It appears that the MATLAB 'griddata' function does not allow you to grid a dataset without interpolation. Is there any function that simply allows my to put this xyz data into a grid of z with dimensions along x and y?

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Answer 1

Walter Roberson 2015-5-22

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If you are trying to create an N x N matrix out of a 1 x N vector then it will only be fractionally populated (1 out of N), and you have not defined what you want to go into the empty places.

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Walter Roberson 2015-5-22

If the purpose is just visual presentation then scatter() might be what you are looking for.

Daniella Della-Giustina 2015-5-26

Yes, scatter may be quite helpful. I had a typo in my initial post. I have clarified above, only x and y are (1 x N) sized vectors, and z is an (N x N) sized vector.

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Answer 2

John D'Errico 2015-5-22

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If you only have a set of points that do not lie on a regular grid, BUT you require a gridded set of points, this is IMPOSSIBLE to solve without interpolation of some sort.

Wanting magic to happen will not suffice, unless of course, your name is Harry Potter. I don't recall any mathematics classes offered at Hogwarts.

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Daniella Della-Giustina 2015-5-26

Sorry--This was a typo on my part. I have clarified above, only x and y are (1 x N) sized vectors, and z is an (N x N) sized vector. The grid is rectangular, and I am hoping to find a tool that allows me to grid the data without an interpolation scheme choice being a mandatory input, as with 'griddata'.

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