[Qgis-user] DEM to contours

[Garth Fletcher]

I have derived contours from QL1 LIDAR data.
In my experience it is necessary to smooth the LIDAR data, generally 
using a Gaussian filter.
The optimum amount of filtering depended on the desired contour 
resolution - lighter filtering for 1' contour intervals, heavier 
filtering for 10' contours. Heavier smoothing makes the contour lines 
smoother, lighter filtering results in jagged lines following to much 
local detail.

See QGIS manual, also:
<https://www.geodose.com/2018/05/how-to-create-contour-lines-in-qgis.html>

I have used several different contouring tools with good results, including:
   Raster > Contour
   Processing > GRASS > Raster > r.contour
   Processing > SAGA > Features > Contour Lines from Raster
   Processing > WhiteboxTools > Geomorphometric Analysis > 
ContoursFromRaster

Garth Fletcher

On 1/19/26 10:02 AM, qgis-user-request at lists.osgeo.org wrote:
> From:<riaanb at iafrica.com>
> Subject: [Qgis-user] DEM to contours
>
> I am trying to get a contour(s) line(s) derived from a DEM. I am using the
> Raster Extractor (from Raster Processing Tool).