If you use a dissolver to merge the overlapping polygons and tick generate a list, using your filename attribute, you can then use a list concatenator to create your desired outcome

HI @egomm, thanks for the help. This worked part of the way. I've managed to get the list to create in a separate column as you suggested. But, it is bringing in every tiff file name that is within a contiguous bunch that have two values, rather than just the two tiles that directly overlap. Can I get it to isolate just the directly overlapping tiles? Thanks for the help.

B

Are you able to share a screenshot of your data? There are number of spatial comparison transformers that will build a list that you can use. Without seeing the data it's hard to recommend what would be best.

It may be that you could just negative buffer your data and then dissolve so adjacent polygons are not dissolved but true overlaps are.

I've attached screenshots of the data in the folder.

The attribute table of the index I'm trying to make.

The grid index itself.

An example of the tiff tiles, there are 79 tiles in the screenshot below.

Thanks for the help.

B

If the grids are identical, you can use the matcher to build the list. Match on 2d geometry, and tick generate list, then concatenate the list on features that come out the SingleMatched port. Everything else will be output via the NotMatched port

Thanks this worked a treat. You are great.