Converting vector and raster data

In this section, we will use the Processing Toolbox to access tools, rather than using the menu bar. Ensure that the Processing Toolbox Panel is visible.

Convert vector to raster (rasterize)

Download: Dominica rainfall vector file

Load the vector file.
In the Processing Toolbox search field, type rasterize.
Double-click Rasterize (vector to raster).
Select rainfall as the input layer.
Select RAINFALL as the Field to use for a burn-in value. This will ensure that the rainfall values are added to the output.
Select Pixels as the Output raster size units.
Enter 100 for the Width and Height. A higher number produces a higher resolution and better visualization.
Set Output extent --> Calculate from Layer --> coastline.shp.
Set the new file name under Rasterized.
Click Run to generate the raster layer.
The new raster will be visible in the Layers Panel.
Click Close when finished.

Convert raster to vector (vectorize)

Convert the new rainfall raster back to vector format.

In the Processing Toolbox search field, type polygonize.
Double-click Polygonize (raster to vector).
Select the rainfall raster as the input layer.
The rainfall values used in the vector conversion above will be added to the new vector. Type rainfall in Name of the field to create.
Set the new file name under Vectorized.
Click Run to generate the vector layer.
The new vector will be visible in the Layers Panel.
Click Close when finished.