I created an NDVI map, I want to calculate area of vegetation verses the respective NDVI value of the given map. Which tools are used for this process and what steps are required?
If I have understood your question correctly you have created a raster which is an NDVI of your area of interest and you want to create a graph of area versus NDVI value, is this correct?
Your NDVI raster will be of type float and with therefore not have an attribute table. You could multiple this up by say 1000 to move the decimal place and convert to an integer grid. This will allow you to create a raster attribute table (number of pixels for each value). You could then copy that into your preferred graphing application and plot. You would need to convert the number of pixels to an area value first and divide your NDVI values to return them to their original value.