Another source of information is the elevation map shown in Fig. 2. Each grid cell represents 1 km2 and
its elevation was computed as the average of the elevations at 4 discrete points within the cell. The
relief is dominated by the two main Algarve’s mountains: the Monchique (left) and the Caldeira˜o (right).
Table 1 indicates that the correlation between rainfall and elevation ranges from 0.33 to 0.83, hence it seems
worth accounting for this exhaustive secondary information into the mapping of rainfall.