{ "name":"DISASTERS_202510_HURRICANE_MELISSA/202511_sentinel2_bndvi", "title":"DISASTERS_202510_HURRICANE_MELISSA/202511_sentinel2_bndvi", "type":"Map Service", "typeKeywords":["ArcGIS Server","Service","Map Service"], "description":"

Dates of Images:<\/b><\/span><\/p>

Post-Event: November 2, 2025; November 4, 2025<\/span><\/p>

Pre-Event: October 20, 2025<\/span><\/p>

Date of Next Image:<\/b><\/span><\/p>

Unknown<\/span><\/p>

Summary:<\/b><\/span><\/p>

Normalized Differential Vegetation Index (NDVI) maps are produced by converting pixel values to NDVI = (Red \u2013 NIR)/(Red + NIR), NIR indicates the near infrared band. The dynamically generated Normalized Difference Vegetation Index (NDVI) layer is an index for quantifying green vegetation. It reflects the state of vegetation health based on how vegetation reflects light at certain wavelengths.<\/span><\/p>

NDVI change was created by subtracting the cloud-masked post-event NDVI from the cloud-masked pre-event NDVI to show areas of potentially impacted vegetation as negative values (darker shades) and healthy/unimpacted vegetation in positive values (lighter shades). NDVI change can give insights to impacts from an event (like the scouring of vegetation from the riverbeds) but can also show changes in unrelated areas like the clearing of agriculture fields.<\/span><\/p>

This layer is a binary NDVI change polygon (threshold of areas where NDVI decreased by -0.25 or more) for November 2, 2025 as compared to October 20, 2025.<\/span><\/p>

Suggested Use:<\/b><\/span><\/p>

NDVI change: Commonly used to distinguish healthy/active vegetation (positive values) from potentially unhealthy/impacted vegetation (negative values). <\/span>This map shows a binary flag where NDVI decreased.<\/p>

Satellite/Sensor:<\/b><\/span><\/p>

MultiSpectral Instrument (MSI) on European Space Agency's (ESA) Copernicus Sentinel-2A/2B satellites<\/span><\/p>

Resolution:<\/b><\/span><\/p>

10 meters<\/span><\/p>

Credits:<\/b><\/span><\/p>

NASA/MSFC, USGS, ESA Copernicus<\/span><\/p>

Esri REST Endpoint:<\/b><\/span><\/p>

See URL section on right side of page<\/span><\/p><\/div>", "extent":[[819479.7999565506,850991.6059085506],[1976760.0591842039,2007512.9799011215]], "url":"https://gis.earthdata.nasa.gov/gis05/rest/services/DISASTERS_202510_HURRICANE_MELISSA/202511_sentinel2_bndvi/MapServer" }