I am trying to create contour plot concentration data to a map. I followded this link and have interpolated the data as follows:
It is relatively rare, but sometimes we encounter a situation
GdalTools plugin is not activated.
In an extreme case like below, we miss lots of raster tools.
In your case, the Plugin Manager will have below tools activated:
- Interpolotaion plugin
- Raster Terrain Analysis
- Zonal statistics
But probably the GdalTools plugin is unchecked. Ticking it on will solve the issue.
NB. This issue is QGIS 2.18 specific.