Wetlands Atlas - Ministry of Environment and Forests

• Extraction of wetland extent :
MNDWI, NDPI and NDVI image was used to extract the wetland boundary through suitable hierarchical
thresholds.
• Extraction of open water :
MNDWI was used with in the wetland mask to delineate the water and no-water areas.
• Extraction of wetland vegetation :
NDPI and NDVI image was used to generate the vegetation and no-vegetation areas within a wetland
using a suitable threshold.
• Turbidity information extraction :
MNDWI image was used to generate qualitative turbidity level (high, moderate and low) based on
following steps:
a) Conversion of post and pre-monsoon water spread polygons into Area of Interest (AoI).
b) Grouping of all AoIs excluding all non-wetland areas into a single entity.
c) Generate a signature statistics like minimum, maximum, mean and standard deviations.
d) Generate a raster turbidity image through a model for AoI only with conditional categorisation.
e) Convert the raster into vector and update the attributes or edit the water spread layer (copied as
turbidity layer) in polygon mode so as to retain all the attributes.
f) Assign turbidity classes as per the table 3.
Table 3: Qualitative turbidity ratings
Sr. No. Qualitative Turbidity Conditional criteria Hue on False Colour Composite (FCC)
1. Low > +1σ Dark blue/blackish
2. Moderate > -1σ to