Assignment+February+8,+2011

In this assignment you will work with global MODIS images. You will work on:
1) understanding the MODIS file names 2) calculating vegetation indices 3) sub setting based on ROIs 4) creating color-coded images for display

In this assignment you need to decide on 3 images to work with. You need one image recorded during the spring, one recorded during the summer and one recorded during the fall. You may decide yourself on the exact three images (there are 45 to choose from).

Here are some steps that will help you complete this assignment. Images are available under Dip:\Data\MCD43C4\MCD43C4. Copy the three images that you intend to work with to your own directory on dip.
1) Open the first image with the MODIS conversion toolkit. Do not worry about reprojecting the data. Global data is delivered in lat/lon projection which works well for our goal. 2) Decide which vegetation index you want to calculate (e.g. NDVI, NDWI, EVI, EVI2, NDII, others?). 3) Determine which bands are part of your vegetation index. Make sure that you understand the wavelength of the MODIS bands. 4) Use band math (Basic Tools --> Band Math) to calculate your index. Equations in band math are very simple, e.g.: (b2-b1)/(b1+b2) 5) Use ROIs to subset the image for your tile. (Tools --> Region of Interest --> Restore save ROI file --> open MODIS_Tiles_ROI.roi under the Data\ROI folder in DIP). 6) Delete all ROIS except for the one of your tile. They are named according to the tiles. 7) Subset the global index by ROI (In the ROI Tool: File --> Subset Data via ROIs). 8) At this point you can do one of two things: a) save your index file and open it in ArcGIS to create a map; b) Use Tools --> Color Mapping --> Density Slice to create a color image. Make sure that you adjust the classes to delete incorrect values. 9) Save your map as a jpg. 10) Repeat for each of the three seasons.

What to upload on you Wikispace page:
1) One image for each season with appropriate labels, e.g. which index you are displaying and which image dates you decided to use. 2) An explanation of why you decided on a certain index. For example, if you work in the middle of the tropical rain forest, you may not want to use NDVI since it saturates. 3) An explanation of why your images look like they look.