I've got a dataset of tiles with individual attributes (NAME,date,sensor). All tiles have the same size. After dissolving layer, in some locations tiles with the same NAME attribute overlap each other but have different sensor and date I need to merge geometry of tiles and concatenate sensor and date attribute separated with sign "/". Is there any way to do it with the QGIS field calculator and "Join attributes by location"? I have tried use "Join attributes by location" but as an output still I get overlapping shapes.
Use the (criminally underused) 'Aggregate' tool in the Processing Toolbox.
first_value as the aggregate function for the
name field, and
concatenate_unique for the other two fields, using
/ as the delimiter (if that's how you want it).
Sample data - note two distinct name values,
The tool will concatenate attributes based on the order of your features in your source file.
If you want the concatenated values to be in a specific order regardless of source file feature order, then you may need to either (a) use Virtual Layer to set the order of your features before concatenating, or (b) post-process the aggregated data using an expression like below in Field Calculator (may be cumbersome if you have lots of fields or need to run the aggregation multiple times).
For example to make sure the aggregated sensor field shows
sensor1/sensor2 instead of
sensor2/sensor1, use the expression below in Field Calculator on the aggregated layer: