The values are representative of increases and decreases of NDVI values in 10% increments. An increase or decrease of less than 10% is considered to be an area of "no change". The areas of increase are shown in shades of green indicating an increase in the amount of vegetation and the areas of decrease are shown in shades of brown indicating a decrease in the amount of vegetation. Value Distribution: This subset area of the coastal corridor includes the city of Biloxi, the Sand Hill Crane Refuge, and the mouth of the Pascagoula River. Location: Change Detection Imagery: Projection: Datum: Landsat Thematic Mapper (LS 5, 7) Mississippi Transverse Mercator (MSTM) North American Datum of 1983 Mississippi I-10 Coastal Corridor Change in Normalized Difference Vegetation Index % CONTACT INFORMATION: Copyright © 2001 CGTC, Mississippi State University Dr. Roger L. King NCRST-E Consortium Director (662) 325-2189 [email protected] Dr. Charles O'Hara NCRST-E Consortium Coordinator (662) 325-2067 [email protected] Map prepared by John Cartwright, Computational GIS/RS Lab The calculation of Normalized Difference Vegetation Indices (NDVI's) can be very useful in the generation of a land-use/land-cover classification. NDVI's can provide useful information about the health and amount of vegetative cover across the landscape. The comparison of NDVI's can show seasonal variations within vegetative cover, helping to distinguish between deciduous and evergreen forest types. Comparisons can also be used to show variations of vegetative cover over longer temporal periods. The magnitude of change from multiple NDVI's can be tabulated in various ways. One such way would be to look at the raw difference in the NDVI values from year one to year two. However, looking at the percent change from year one to year two could be more useful in terms of the overall assessment of change within an area. The upper image depicts the percent change from February 1991 to February 2000 based on the calculated NDVI values. The percent change was calculated for increase or decrease in NDVI values normalized to the value of global maximum increase or decrease between the two images. Increases indicate the addition of vegetation and decreases indicate the removal of vegetation. Prominent areas of increase might indicate the regeneration of a forest after an earlier harvesting and areas of decrease might indicate the removal of vegetative cover for land development. > 40% 30 - 40% 20 - 30% 10 - 20% -10 - -20% -20 - -30% -30 - -40% > -40% No Change EXPLANATION Amount of Change in NDVI Values |NDVI Normalized Difference Vegetation Index from Landsat satellite imagery acquired on February 14, 1991 Normalized Difference Vegetation Index from Landsat satellite imagery acquired on February 15, 2000 Scale: Upper Panel Lower Panels 1: 175,000 1: 425,000