Pay attention to the Ticks parameter, and this example is used in documents.
Here is one way to do it. First create some sample data:
mat = Table[Exp[-(x^2 + y^2)], {x, -2, 2, .1}, {y, -2, 2, .1}]; aCol = aRow = Round[mat[[20]], 0.01];
Place it in 3D. I decided to show every tenth mark of all possible. list[[;; ;; 10]] list[[;; ;; 10]] selects every 10th element of the list.
ListPlot3D[mat, Ticks -> { Transpose[{ Range@Length [aRow], aRow}][[;; ;; 10]], Transpose[{ Range@Length [aCol], aCol}][[;; ;; 10]], Automatic}]

Plan it in 2D. ListDensityPlot has Frame (not Axes ) by default, so we use FrameTicks
ListDensityPlot[mat, FrameTicks -> { Transpose[{ Range@Length [aRow], aRow}][[;; ;; 10]], Transpose[{ Range@Length [aCol], aCol}][[;; ;; 10]], None, None}, Mesh -> Automatic]

Update
If you don’t need arbitrary ticks, just a different range for regular labels with linear spaces, you can use the DataRange parameter as follows:
ListPlot3D[mat, DataRange -> {{0, 1}, {0, 1}}]

If you still need data in the format {x,y,z} (since the coordinates are not evenly distributed), you can create it with
Join @@ MapThread[Append, {Outer[List, aRow, aCol], mat}, 2]