Divide an image along lines and indexing different segments they produces

i wanted to plot axes at a specific points but couldn't. so added lines using hline and vline commands. now i have four segments at that point, but since they are not equal i can't use blockproc. but what need is i have got to index the four segments so that i can determine positions with respect to the intersecting points as quadrant position treating that point as origin.And I could also work with drawing normal axes, putting that point at origin and thus dividing the overall image into four indexed quadrants. Any of these two approach will do for me. but sadly i can't seem to do any. I'll be really grateful if anyone could help.Thanks.

Answer 1

[Walter Roberson]

Subtract the index of the origin point to come up with the mapped coordinates.

x_mapped = ColumnNumber - x_center;
y_mapped = RowNumber - y_center;

Note that x corresponds to columns (second coordinate), not to rows (first coordinates)

[Tasneem Tabassum]

thanks :D ... but can you help me with after getting the mapped coordinates as origin how can i index the four axis quadrants!

[Walter Roberson]

... You don't? You index in unmapped space.

Perhaps what you are looking for is something like:

YourMatrix(1:y_center, 1:x_center, :)    %upper left
YourMatrix(y_center+1:end, 1:x_center, :)    %lower left

and so on?