The use of remote sensing for the study of vegetation and the urban is at the heart of the objectives of the Recovery Observatory. An internship in 2018 has been set up in order to assess the impacts of the hurricane in the Great South of Haiti. The study focused in particular on the monitoring of the city of Jérémie and the evolution of the vegetation of several areas of the hinterland.

Tacking indices :

• Urban : index of cuirass and shine
• Vegetation : NDVI index

Work done by Xavier Tardieu monitored by IRD and CNES

Imagery : Pléiades (Urban), Sentinel 2 L2A (Vegetation)

Conclusion (Summary)

The study from the classifier Kmeans on the city of Jérémie shows two results. The first shows the very significant fall of urban vegetation. The majority of the vegetation including the one covering the buildings was blown down.

K Means classification and urban footprint of the city of Jérémie

The second result, which focuses on buildings, shows that the hurricane caused significant damage. The informal building area was more affected than the formal building area.

However, confusion between the post-hurricane classes made the classification exercise difficult. The lack of field data makes it difficult to assess the types of damage that have been caused.

On the theme of vegetation, all areas were impacted with a drastic fall in the NDVI to a maximum of the median around 73%. One year later, in September 2017, the vegetation recovery is observed (median increase of about 55%) even though the NDVI values remain lower than those before the hurricane.

Evolution of NDVI pre and post hurricane Mathieu on Sentinel 2 Grand'Anse / Sud tile

Nevertheless, these impacts and this recovery are strongly dependent on the location of each zone and the type of vegetation. The lack of field data thus greatly limits the accurate assessment of damage.

Final delivery is available in the attached files :
Attached you will find the internship report and the final presentation of the internship.