I have a data set of water level ranging from -6 m below sea level to +30 meters. But when I use the model example for creating contours from points, the minimum contour value is zero (0). What can be the reason for that?
(I'm using QGIS 2.4.0)
UPDATE: I've tried to run the model in QGIS 2.6 and get . It works fine when running another data set with only possitive values. What is the meaning of the error?