Now we have a table with the distance along the river and the corresponding elevation, we can visualise the profile using the Data Plotly plugin.
1. Install the Data Plotly plugin.
2. Click the icon to open the Data Plotly panel.
3. In the DataPlotly dialogue choose the Bar Plot as Plot type. Select Sample1kmZ as Layer with X field distance and Y field DEM_1. Edit the X field to convert distance to km.
4. Click to change the title and legend settings.
5. Fill in the dialogue as in the figure below and click Create Plot.
Now you can see the result: