I have a river network, extracted from a DEM. Then I split it to shorter segments. The split adds some points (as shown in figure) too near to each other. I wonder how I should remove those small lines and simplify the segments?
You have a number of tools in QGIS via GDAL and GRASS etc. The most obvious is to go
Vector->Geometry Tools->Simplify geometries and set the tolerance for the distance between vertices. This will eliminate vertices closer than a the set distance (and thereby eliminate the short lines).
In GRASS (via the Processing Toolbox), there is v.generalize.simplify and in this tool you can choose the algorithm by which thesimplification takes place (such as Douglas-Peuker etc).
Thanks a lot guys. I just wanted to take a moment to express my gratitude to grass and qgis developers. I solved the problem with my rivers using simplification of the vectors tool. Many thanks to the people in stack exchange community for the wonderful and great support. I doubt that any commercial software developer can afford to be this much effective. :)