A novel strategy for wetland area extraction using multispectral MODIS data

Results of rigorous data mining reveal that out of 24 input layers of MODIS (1 km) data (22 optical MODIS bands, NDVI and WMI), only 4 input layers (WMI, NDVI, MODIS bands - NIR band 2 and SWIR band 6) are best suited for delineation and mapping of wetlands. This study also corroborates the usage of WMI, a newly developed index with combination of visible and short wavelength infra red (SWIR) MODIS bands, as the most optimal input layer to separate wetlands from the other land use class types (barren land, agricultural land, rivers/canals/streams, forest, wasteland/gullied or riverine land). It was observed that the magnitude of mapped wetland areal extent using MODIS (1 km) data varied from 105,053 ha in 2010-2011 to 111,479 ha in 2011-2012 accounting for 0.44% (2010-2011)-0.46% (2011-2012) of the total geographical area of Uttar Pradesh, India. Seasonally, monsoon season displayed maximum wetland area with overall accuracy of 92% whereas summer season exhibited minimum wetland area with overall accuracies varying from 85 to 87% during both the sampling years. The output of the present research work will not only facilitate to improve the wetland area estimates but also provide an important input for climate change predictions in wetlands over large areas.