Use meshgrid with two different vectors

Question

I want to create a grid what is saved in a matrix (nx3) (here: obsPos) with zeros in the third column. The grid should be uniformly spaced. The matrix should be defined by two vectors (dim: 3x1).

Objective: To create a mesh what is x meters long and y meters wide and save positions of this mesh into a matrix. This mesh should be evenly distributed, eg each mesh panel is one square meters big.

Cheers!

obsXlimit = 50; % Define size of the observer grid in x-direction (m)
obsYlimit = 20; % Define size of the observer grid in y-direction (m)

obsXspanVector = [obsXlimit 0];
obsYspanVector = [0 obsYlimit];

[obsX obsY] = meshgrid(obsXspanVector,obsYspanVector); % Generate X and Y data of the observer positions

obsZ = zeros(size(obsX, 1)); % Generate Z data of the observer positions (always with obsZ = 0)

obsPos = [obsX(:), obsY(:), obsZ(:)]; % Save every observer position

Answer 1

You state uniform grid, this is obtained using start:step:stop with start , step and stop being the point where the grid starts, the stepsize and where it ends respectively. As it seems, you have the grids as

obsXspanVector = [obsXlimit 0];
obsYspanVector = [0 obsYlimit];

Wich will make a grid only consisting of the start and endpoint. Additionally, as one square has to be 1 square meter big, I presume the stepsize should be one:

obsXspanVector = 0:1:obsXlimit;
obsYspanVector = 0:1:obsYlimit;

Then you can generate the grid for x and y with

[obsX obsY] = meshgrid(obsXspanVector,obsYspanVector);

Then to avoid forgetting, redefine the arrays obsX and obsY to be their Nx1 equivalent.

obsX = obsX(:);
obsY = obsY(:);

Then you can draw the zeros needed, though noticing that zeros with 1 input makes a square matrix, and multiple inputs (possibly as array) give an array of the specified size

obsZ = zeros(size(obsX)); %size(obsX) = [N, 1]

and finally, you can merge

obsPos = [obsX(:), obsY(:), obsZ(:)];