im looking for a way to get the quantity of lines from a line-layer that intersect the different polygons of a polygon-layer;
One line-layer with a clutter of lines, defined by ID, which represent the flight-activity of birds in a specific area. The layer is called "lines".
One Polygon-Layer with a specific grid. The layer is called "grid".
I need for every square-polygon from the "grid"-layer the quantity of different lines from the "lines"-layer, which intersect them. The Value is supposed to show up in a new column of the attribute-table of the "grid"-layer called "LineCount" in this example (the layers in the screenshot are just examples, the original ones have much more lines, so it is not practical to count them by hand ;-)).
The aim is to visualize the density of flight-activity in a raster-like map.
I guess there might be some solution within the refFunctions-plugin, but I'm not able to figure it out.