**3. Results**

### *3.1. Accuracy of Supervised Classifications*

The overall accuracy values obtained were above 90% (Table 3), and the Kappa coefficient indicated values between 92 and 99%, thus suggesting a better distinction between land cover types.

**Classification 1 Classification 2 Image Mosaics Classified Overall Accuracy (%) Kappa (%) Overall Accuracy(%) Kappa (%)** 1986 94.08 97.04 95.36 98.78 1998–1999 98.11 94.08 98.44 97.66 2010 94.52 96.38 96.46 97.36 2021 95.09 92.52 94.35 92.43

**Table 3.** Overall accuracy and Kappa coefficient values from supervised classifications of Landsat image mosaics of the Port-au-Prince agglomeration from 1986, 1998–1999, 2010 and 2021 based on the maximum likelihood algorithm.

Classification 1 refers to the segmentation and qualification of the urban–rural gradient zones, and classification 2 to the land cover types classifications within the urban, peri-urban and rural zones.

### *3.2. Mapping and Quantification of the Spatial Changes in the Urban, Peri-Urban, and Rural Zones in the Port-au-Prince Agglomeration*

A total of four land cover maps were produced following the supervised classification of Landsat images, illustrating the dynamics of the urban, peri-urban, and rural zones of the Port-au-Prince agglomeration in 1986, 1998–1999, 2010, and 2021 (Figure 2). The visual analysis of the spatial dynamics shows that the urban and peri-urban zones are in constant spatial progression between 1986 and 2021 in the north and east of the study area on a rural matrix that has registered a regressive dynamic (Figure 2).

**Figure 2.** Land cover maps of the Port-au-Prince agglomeration obtained from supervised classification of Landsat images from 1986, 1998–1999, 2010 and 2021 based on the maximum likelihood algorithm. The black lines correspond to the boundaries of the municipalities.

The urban zone experienced a net increase of 612.33% in the landscape between 1986 and 2021, with its area increasing from 8.19 km<sup>2</sup> to 58.34 km2. However, it should be noted that the most dramatic spatial increase in the urban zone occurred between 2010 and 2021, with a net increase of 229.42%. The peri-urban zone also increased in acreage from 45.57 km<sup>2</sup> in 1986 to 242.93 km<sup>2</sup> in 2021, with a rate of change of 433.09%. In contrast to the urban and peri-urban zones, the rural zone experienced a regression in acreage from 1697.47 km<sup>2</sup> in 1986 to 1449.82 km<sup>2</sup> in 2021, a net loss of 14.59% compared to 1986 (Table 4).

**Table 4.** Net area increase between 1986–1998/1999, 1998/1999–2010, 2010–2021 and 1986–2021 of the different zones (urban, peri-urban, rural) corresponding to the agglomeration of Port-au-Prince.


*3.3. Mapping and Quantification of Land Use Dynamics along the Urban–Rural Gradient of the Port-au-Prince Agglomeration*

Table 5 displays the morphological urbanization status of the 10 municipalities within the Port-au-Prince agglomeration and the land cover change that occurred within each morphological type of municipality. First, four municipalities exhibit a dominance of builtup area, notably Port-au-Prince and Delmas, which bear an urban zone status, as opposed to Cité Soleil and Tabarre, which have a peri-urban status. In the municipalities with an urban zone status, the "built-up and bare soil" class increased to become the landscape matrix (dominant land cover type) in 2021, while the proportion of fields (the dominant land cover type in 1986), woody vegetation, and grassy vegetation decreased (Figures 3 and 4). This seems to sugges<sup>t</sup> the replacement of vegetation under the influence of expansion and built-up densification. Regarding the municipalities with peri-urban morphological status, the evolution of land cover shows a transition marked by the replacement of fields, which constituted the landscape matrix in 1986, 1998–1999, and 2010, by the built-up area and bare soil that became the dominant land cover type of the peri-urban zone in 2021. During the same period, the proportion of woody and grassy vegetation decreased in the peri-urban zone between 1986 and 2021 (Figures 3 and 4).

In contrast, the municipalities of Croix des Bouquets, Pétion-Ville, <sup>L</sup>éogane, Gressier, Kenscoff and Carrefour are characteristic of rural zones (Table 5). Within these municipalities, a degradation of woody vegetation (the dominant land cover type in 1986) and grassy vegetation was noted, marked by their replacement with fields, which increased in proportion to become the new landscape matrix in 1998–1999, 2010, and 2021. In these municipalities with a rural morphological status, the area of "built-up and bare soil" increased three-fold in the landscape over the entire study period, with a more marked evolution between 1998–1999 and 2021 (Figures 3 and 4).


**Table 5.** Morphological status of the municipalities along the urban–rural gradient of the Port-au-Prince agglomeration according to [43] typology. These results are derived from the supervised classification of the Landsat image mosaics of 2021 based on the maximum likelihood algorithm.

**Figure 3.** Land cover maps of the Port-au-Prince agglomeration from supervised classification of Landsat image mosaics from 1986, 1998–1999, 2010 and 2021 based on the maximum likelihood algorithm. The black lines correspond to the boundaries of the municipalities.

**Figure 4.** Evolution of the percentage of landscape of different land cover types in municipalities with urban (**A**), peri-urban (**B**) and rural (**C**) zones morphological status. These results were obtained on the basis of supervised classification of Landsat image mosaics from 1986, 1998–1999, 2010 and 2021 based on the maximum likelihood algorithm. The vertical bars represent the standard deviation.
