PBL rapport 550026002 Calibration and validation of the land use ...

Simulated 1993 land use using continuous model
Figure 4.2
Observed 1993 land use (left) and its simulation with the continuous model, using 1993 land use (A) and the multinomial
regression specification (B) as input for the suitability maps.
that underlies this specific allocation model. While assessing
these results, it is important to note that an allocation
surplus in one cell, essentially, leads to a deficit in another
(see the discussion in the Methodology Section). When the
actual ratios are compared, it becomes clear that, according
to this comparison method, the model performs a little
better with an overall correspondence of 75-95%. This mainly
shows the varying impact of using a different data representation
method. For some land-use types (e.g. agriculture) the
fractional comparison performs less well, while for others
(notably commercial and recreation) it suggests a better
correspondence. The latter types of land use may be structurally
under-represented in maps of dominant land-use, as they
tend to cover only small areas.
The level of correspondence is also exemplified by the related
map of dominant land use presented in Figure 4.2B: only marginal
differences to the observed 1993 land use occur. These
differences relate to the presence of slightly more compact
forms, as was also the case with the simulation following the
discrete model.
Calibration results 29