I have polygon data for water bodies in a watershed generated from Google Earth Engine for years 1984-2015. I have one shapefile for each year. (I also have 1 shapefile that has them all combined, attributed with the year, if that helps.) Basically, in the data is showing how the water bodies have changed over time, thus, there are new polygons in later years.
I am looking for a way to aggregate all of the polygons into 1 shapefile but only retain the polygon with the earliest date. So if a polygon has been there since the 1984 data, it will be attributed 1984 but then everything else that overlaps with it will be deleted.
Thanks for any help!