I have a polygon file, where each polygon represents one property. I want to be able to sort the polygons from north to south or vice versa. I need them to be sorted in this way when I export them to a different program. In the other program I want the properties to appear in a north to south order when I visit them one by one.
My first problem is, the polygons don't have information about there coordinates in the attribute table.
How can I add this?
I have tried using the field calculator, but I don't seem to get it right.
And, next step, if I sort them in QGIS, can I somehow "save" that order so that they appear in the same order in the other program?
I have tried the method in the answer below, but I don't get it to work on my data. Then after almost giving up, I read in the help of the field calculator that $y gives the y coordinate of a point.
But I have a polygon layer?
What do I do?