In this video we use the SAGA smoothing lines application to clean up some contours.
QGIS https://qgis.org
SMS https://smsgis.co.za
timestamps
0:35 Extract contours from a SRTM grid
0:59 SAGA Smoothing Lines
3:08 Create new "LENGTH" column
3:30 Calculate line lengths
4:27 Using the Query Builder to exclude lines shorter than 65m
5:25 Labeling the contours