[Help needed] Sample colour in each cell of a grid

Hi All,

First of all, HAPPY OCEANS DAY!

Here is my problem:

I have hundreds of maps of exactly the same size, for which I would need to extract the "value of the colour" in each cell of each map.

There is no way I can get my hands on the GIS data, hence the need to use Photoshop.

Here is a example of these maps:

I hope it is possible to generate a script to super-impose a grid on that map, and then get the colour in each cell. Then I'd just need to convert the colour quote into actual value, and I'm done (but there is not need to use PS for that). I did some research on the internet, but didn't find anything satisfying (I may have not used the right keywords).

Do you think this is a realistic option, or should I just give up right away?

If the answer is "yes, it might be possible", then I might also need your help to write the script

Thanks a lot for your help!

Fred