Here are 40000 points (x,y) on the wafer, how to arrange them into the right row/column, in order to form wafer map?

Question

Hello all friends,
I want to arrange all these phisical points into a logical map, but how many rows and column are not known in advance, we just know:
1. seperation can be given, for example stepX(width) =390.7，StepY(heigh) =318.8
2. some of the points' posX and posY are scaned several times, so deleting redundant data needed.
What's the method to solve this problem?
posX posY
60346 79682.2
59928.4 78089.2
60724 79044.4
61484.2 78085.9
59948.7 79045.6
61479 77767.5
60339.5 79365.1
56052.5 79061.7
56030.9 78113.6
56428.6 78425.4
56436.5 78745.9
57201.8 78106.2
58781.1 79374.2
56448.4 79702.1
56825.3 79066
56440.2 79059.4
57613.9 79700.8
56840.8 79699.7
57989.3 78739.6
58778.9 79692
58772 79048.6
58004.9 79692.7
56057.1 79703.9
57224.6 79381.9
56821.8 78747.1
56422.6 78111.7
57611.8 79379.9
56047.5 78747.2
56827.9 79385.8
56416.1 77793.6
57194.1 77787.8
56048.2 79385.7
58383.6 79060.5
56444.7 79384.2
57587.1 78109.3
Below is a small example to demostrate this case,  just with hundreds of points
From sacnning the wafer：
To form the map：
 Thanks very much,
Deho

Answer 1

Thanks Johnsol,Stevem181 ,GerdW:
display using intensity chart with 2D array data source can be realized,  there are some topics discussing about it. For example, from Stevem181(thread here), and GerdW (thread here). 
And, thanks GerdW again, I use the map image  from his post, everybody can goto that thread for detailed. .
but, I think the diffcult may be the classfication of the data.  The question is like this, let me give an example: Throwing a handfull of beans on the desktop, under this condition without anyother infomation supported, how to segment them in to the best suitable row/coulmn?
for example this is the case:
here is classfication 1:
and here is the classfication 2:
In these two arrangement  surely we think 1th is more suitable than 2th,
for there are too many empty cells in 2th  , indicated by blue color::