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Haiti, Les Nippes, 2021-08-14 Earthquake
Compare Map, Before/After, Drone and Satellite imagery

This map allows side-by-side comparison of pre and post-disaster images. The Selection panel at the top left groups by category drone and satellite imagery. The CNIGS 2014-2015 Ortho layer (20cm resolution) allows to observe the pre-disaster situation. More recent satellite images are available, although they are less accurate. Layers such as OpenStreetMap, official CNIGS road network, elevation, relief are also available.

Drone-UAV Images post-disaster images have a 2-4cm resolution and Satellite Images depending on the captor, have 31-41cm spatial resolution. Depending on the image, more or less detail is available.

CNIGS : Haitian geospatial agency

Comparison of Pre and Post-Disaster imagery

Side by side Comparison of images reveal's the extent of destruction but also the rapid urbanisation in some areas since 2014-2015. With post-disaster aerial photos, preliminary evaluation of building damages in various localities can be made rapidly. While these evaluations let prioritize areas of intervention, more precise evaluations are realized by field observations.

Vertical aerial photos and tree coverage density are factors that limit the observation of buildings and the possibility to assess the damage extent, to see the walls and observe partial structural damages.

To Compare left-right images, we move the bouton Sliding vertical bar left and right. Drone Post-Disaster images cover small areas and are named by one of the town inside the extent.


Layer Selection Panel

To Access list of Left and Right side Layers to compare, you Unfold bouton,   Fold bouton Sections. You Check bouton one or more images that you want to visualize.

To move the map to a specific image, Click on the bouton zoom to extent button beside that image name in the List.

Other layers such as OpenStreetMap, Routes CNIGS, Elevation and relief are also provided. To use the OSM background image to locate a building or area, you simply uncheck the overlayed imagery to temporarily hide it.

Pierre Béland

Help - Images selection and Map navigation

Layers Selection - Images Categories

bouton Unfold   bouton Fold Sections

Background image Selection, left and right

bouton Background layer Selection

Right Side - Overlay Drone images


Search for a location

Click on the Search button to open the Search panel; enter a location name (example: Cavaillon, Haiti). From the result list, click to select the location where the map will zoom-in.

Navigation on the map

Pierre Béland