This could very well be a duplicate question, but i can't find the answer in the site.
Using QGIS 3.4, I have two vector layers with polygons and same projections: one with all individual watersheds and the other with cumulated upstream watersheds. The first layer has a field that can be joined with the second, so that each watershed has a corresponding upstream area. The second layer is designed for this specific purpose.
I want to join the layers and then select any watershed, resulting in a selection of that watershed's cumulated upstream area. Exactly what the second layer is designed for.
I can join the layers in the properties tab, and the first layer's attribute table is populated with the second's data. However, when I select the first layers watersheds, nothing is selected in the second layer.
What is the next step I must take to achieve my selecting results?
The description of the second layer states that the polygons are overlapping each other.
Watershed layer: https://www.smhi.se/polopoly_fs/1.24469!/Menu/general/extGroup/attachmentColHold/mainCol1/file/aro_y_2012_2.zip
Upstream area layer: https://www.smhi.se/polopoly_fs/1.31173!/Svaro.zip
Both layers are in SWEREF99TM
