Break data up into groups then highlight the lowest number in the group. Any suggestions?

[jeevesme]

I have A LOT of data that is exported from a measuring device. This scan device takes measurements every .093" which gives me thousands of readings even for a "small" scan. In order to make this data a bit easier to understand, i need to "break it up" into 1" squares and then highlight the lowest number in that 1" square. I'm decent with Excel but I'm not sure how to tackle this one. Any suggestions would be greatly appreciated. I've attached an example of the data that is compiled from the machine.

[dflak]

What is a one-inch square? Could you work out an example or two so we can catch onto the logic? Thanks.