I have a map with different zones where I have drawn isochrones -where I will arrive within 15 min, within 30 min and so on. The picture attached shows the 15-120 min isochrones.
This is set as a matrix table, where each column represents a zone (D2000, D2001, and so on) and every row is the time between the zone selected and the rest of the zones.
The plot currently shows travelling distances from D2000, and if I want to select a different origin, I go to properties > style > column and I chose a new one (i.e.: "D2001"). Then, I will get the isochrones for this new origin "D2001" as the properties (eg: Colours) will remain the same (so I don't need to change anything just ask qgis to refresh the layer to get the new values).
The problem is that I need to present something more interactive. The idea is to avoid the "properties > style > column" but just to select a value from the screen (using "select features by freehand" -only one feature each time-) and automatically run the "properties > style > column" process to show the selected zone as the origin for the new isochrones.
I believe it could be done in python, but unfortunately I don't possess that knowledge yet (it is my goal for 2016!) but I need this map done the sooner the better.
Basically, it would be something like this:
- layer selection
- select features by freehand
- selection of (just) one zone ("D2000")
- go to properties > style > column
- change default column ("ZONE") to select "D2000"
- allow any type of reset to set the default column "ZONE" in order to start the process again.