Using MODIS Terra TIF file to get land-water map

Question

• I am able to read the modis image into Matlab. And I want to do some simple calculations. But, how do I access the different bands in Matlab?
• So, I have downloaded the 7-2-1 tif data (Not HDF) from the MODIS website and I want to create a map that shows flooded and non-flooded regions. I would like to do ISODATA classification in Matlab (And also in ArcGIS or ENVI). So far I have read the data into both ArcGIS and Matlab. But I am not able to use the different bands (7-2-1).

But I am not sure how to proceed.

This is an example MODIS image: http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=USA6.2013323.terra.721.1km

And I am using Geotiffread

I have

ArcGIS 10 (All tools) Matlab ENVI

Could you please guide me?