In previous sections, we covered the querying of the immediately available properties of vector layers (for example, the CRS definition or attribute table), and the modification of vector layers involving only the attribute table component (for example, removing the attribute table or subsetting the layer according to it). In the next two sections, you will learn to examine and modify the geometrical component of vector layers. In this section, operations involving a single vector layer, such as reprojection and area calculation, will be covered. In the next section, we will deal with operations involving pairs of vector layers.
Reprojection is the conversion of all the coordinates of a spatial object from one CRS to another. Note the distinction when specifying a CRS (which we previously did with airports), where only the CRS definition associated with the layer is modified, leaving the coordinates unaltered. The reprojection...