Automate the selection of duplicate geometries with QGIS3

Question

I have a layer of buffers calculated from watercourses. Each watercourse/buffer has a Strahler Order (0 to 7).

I need to delete overlaps between buffers order 0 and buffers order 1 to start, but choosing to keep the highest order (1), that's why I can't simply apply "remove duplicate geometries", as I did first on seperate layers of buffers with the same order)

Here is a summuary of the several steps I apply, mainly using models :

• create one layer for buffers of each order
• apply v.clean tool, for area and the cleaning option "rmarea" that cuts polygons according to overlaps. Before : After :
• Like I now have duplicated geometries at intersections, I apply remove duplicates

I did these steps for each order, and now I would like to remove duplicates of the lowest order. I tried the following steps :

• merge buffers order 0 and 1
• apply v.clean with the same parameters as below
• select duplicates using the following expression, but it doesn't work :

intersects(  $geometry,  geometry( get_feature('Arthabaska_Buffer_RH_CE_D_20m_ordres01','ID_O_Str_1',0)))

• In the previous selection, select buffers order 0 and remove them

What's wrong with this expression, and/or is there an easier way to do ?

Answer 1

I'm still interested in knowing how to do it with an expression and will add soon files to make tests, but I finally decided to do it in another way:

• create a buffer of 1m around the buffer of the highest order (i.e 1)
• select buffers with lowest orders (i.e < 1) in the layers of buffers with all orders after v.clean
• select by location inside the previous selection buffers within the 1m buffer
• delete selected features