Question: I have my OSM data in a local server.
I already done with the contour lines using [Phyghtmap](http://wiki.openstreetmap.org/wiki/Phyghtmap) and achieve a good result.

Now I'm trying to show the relief "shadows" like this beautiful map:[![enter image description here](https://i.stack.imgur.com/b6i3y.jpg)](https://i.stack.imgur.com/b6i3y.jpg)

I know it is not OSM data, just some kind of transparent PNG layer, but I don't know how to create it...

**EDIT**

By reading [this](https://thangbui.wordpress.com/2012/06/24/create-map-tiles-from-srtm-data-gdal-and-imagemagick/) I'm now able to convert my HGT files downloaded by Phyghtmap to GeoTIFF but it have a very bad resolution...

[![enter image description here](https://i.stack.imgur.com/xRoON.jpg)](https://i.stack.imgur.com/xRoON.jpg)

Answer: 
While the plugin snaileater suggested should work, I think you will have an easier time if you convert your 4 columns to WKT - as you already mentioned in the question - particularly, if there are other columns in the CSV (containing transport link attributes).
Points have usually (...) 2 coordinates, what u try to import is obviously **flow map** data with origin/destination information. There are some plugin dedicated to this kind of import ... look for example at **[Oursins plug-in](http://plugins.qgis.org/plugins/Oursins/)** in the repositories, that will help u import that kind of data.