For one who hardly ventures into raster GIS, I gave QGIS raster tools a try. I downloaded a natural earth file then panned over to Malaysia and zoomed-in farther. Raster data is heavy so it is wise to clip unnecessary area away and using the the Clipper, it worked fined then for the heck of it, I tried the Contour and even that worked out fine. I must say, QGIS is very user-friendly here but I must admit one has to use some common sense to choose the appropriate places to click and get results. I also found it easiest to increase the number of contour lines simply by reducing the number of intervals say shown below from 10m to 5m to 1m though it can get to be a bit jagged when the contour points are too far apart as shown by the 1m intervals.
