## 5 Results and Discussion
### Monitoring Land Conversion Using Artificial Patches  
At the end of the classification process we developed, we extracted images of artificial areas from the RapidEye images of 2009 and the IRS images of 1996-1997 (Figure 5).  
Two artificial patches were generated covering the four coastal departments in Languedoc-Roussillon in 1996-1997 and 2009. An extract of these results is shown in Figure 6.  
These two artificial patches were then combined and used to identify any increase in urban sprawl between 1996-1997 and 2009, and also to quantify land conversion. Figure 7 shows the spatial progression of land artificialization. Figure 8 shows an extract of artificial sprawl at a coarser scale.  
Figure 5: Result of the classification: Artificial areas in 1996–1997 and 2009.  
Figure 6: Result of the dilation/erosion process: artificialized patches in 1996–1997 and 2009.  
The increase in artificial areas in our study area amounted to 20,000 ha, _i.e._, 0.8% of the total area of the four coastal departments. However, this represents an approximate 8% increase in artificial areas (Table 4).  
These results illustrate the differences in the degree of pressure on each territory in the study area. The Herault and Gard departments showed the largest increases in artificial sprawl: approximately 7,000 ha in both departments and an increase in urban sprawl of 9% and 9.9% respectively. Figure 9 shows the artificial sprawl for each department.  
\begin{table}
\begin{tabular}{|c|c|c|c|c|} \cline{3-5} \multicolumn{1}{c}{} & \multicolumn{4}{c|}{**Area in hectares**} \\ \hline \multicolumn{1}{|c|}{**Name of**} & \multicolumn{1}{c|}{**Total Area**} & \multicolumn{1}{c|}{**Artificialized Patch**} & \multicolumn{1}{c|}{**Artificialized**} & \multicolumn{1}{c|}{**Artificial**} \\ \multicolumn{1}{|c|}{**Departments**} & \multicolumn{1}{c|}{**(ha)**} & \multicolumn{1}{c|}{**in 1996–1997**} & \multicolumn{1}{c|}{**Patch in 2009**} & \multicolumn{1}{c|}{**Sprawl**} \\ \hline Pyrenees-Orientales & 416,139 & 43,174 & 46,349 & 3,175 \\ \hline Herault & 624,789 & 77,475 & 84,470 & 6,995 \\ \hline Gard & 588,826 & 68,746 & 75,583 & 6,837 \\ \hline Aude & 634,700 & 53,000 & 55,304 & 2,304 \\ \hline Total & **2.264.454** & **242.396** & **261.707** & **19.311** \\ \hline \end{tabular}
\end{table}
Table 4: Increase in artificialized patch areas between 1996–1997 and 2009.  
Figure 7: Combining the artificialized patches enabled us to locate and quantify artificial sprawl between 1996–1997 and 2009—fine scale extract.  
Figure 8: Combining the artificialized patch enabled us to locate and quantify artificial sprawl between 1996–1997 and 2009: Coarse scale extract.  
To identify the nature of these changes, we also produced a roadless \"artificial patch\". Table 5 shows that in this case, growth for the four departments analyzed increased from 8% to 18%. The increase in off-road artificial areas was highly significant (18% in 12 years). It mainly reflects the urban sprawl phenomenon. On the other hand, although including roads in the artificial patch leads to an exhaustive representation artificial areas, it partially smoothed land conversion. This is explained by the density of the existing road network and its marginal development that minimize the overall artificial sprawl.