I have a shapefile of contour lines, with an
ALTITUDE attribute with the height ASL in metres. The source data is in 0.5m intervals, but I'd like to filter it down so I get contour lines at (for eg.) 5m intervals.
I tried doing a query on the layer using
"ALTITUDE" % 5 = 0, which almost worked except I get two contour lines where I would expect one - I'm guessing this is because
% is an integer operation so
245.5 % 5 and
245.0 % 5 both = 0?
Is there a better way to filter for 5m (or some other interval, say 1m or 2.5m) data?