Maybe this works. Hard to tell because the randi images are not so comparable to your image.
Basic idea is to combine the coordinates x1 and x2 into x as well as y1 and y2 into y. Then sort x and sort y and find the values of x1,x2,y1,y2 in x and y to get indices. These indices should correspond to the place where A1 and A2 have to be in the merged matrix A.
clearvars
close all
clc
%% Definitions
x1 = [1.10, 2.11, 3.07, 4.10, 5.09, 6.10, 7.12, 8.10];
x2 = [5.45, 6.43, 7.46, 8.45, 9.44, 10.42, 11.43];
y1 = [-4.30, -3.29, -2.35, -1.31, 0.30, 1.28, 2.32, 3.30];
y2 = [-3.70, -2.69, -1.67, 0.71, 1.70, 2.72, 3.71, 4.68];
A1 = randi(10, length(x1), length(y1));
A2 = randi(10, length(x2), length(y2));
% Initialize the merged matrix with NaN
A = NaN(numel(y1) + numel(y2), numel(x1) + numel(x2));
% combine x1, x2
x = [x1 x2];
% combine y1, y2
y = [y1 y2];
% sort the combined coordinates
x = sort(x);
y = sort(y);
% Use ismember to get the indices of x1 in x
[~, A1_x] = ismember(x1, x);
% Use ismember to get the indices of y1 in y
[~, A1_y] = ismember(y1, y);
% Use ismember to get the indices of x2 in x
[~, A2_x] = ismember(x2, x);
% Use ismember to get the indices of y2 in y
[~, A2_y] = ismember(y2, y);
% Write A1 at the corresponding position in A
A(A1_x, A1_y) = A1;
% Write A2 at the corresponding position in A
A(A2_x, A2_y) = A2;
figure
imagesc(x1, y1, A1)
figure
imagesc(x2, y2, A2)
figure
imagesc(x, y, A)
Another approuch would be to define a common mesh and use interp2 to place the two pictures onto these mesh or to use imfuse if you have the Image Processing Toolbox.
