I am trying to analyse the images that I downloaded from MODIS, which are the Vegetation Indices 16-Day L3 Global 1km. With this data I want to analyse the change in vegetation over the years in a area which now suffers with drought.
So, what is the best tool to do this? The files are all in .hdf format, and I do not know how to work with this or convert to a more useful format.
QGIS, free software, has support for HDF4 and HDF5 images. You can open them perfectly with this software. These images have the sinusoidal projection (+proj=sinu +lon_0=0 +x_0=0 +y_0=0 +a=6371007.181 +b=6371007.181 +units=m +no_defs) and they can be later exported with another format and projection using the Raster -> Projections -> Warp (Reproject) option menu.
Below, you have an example in my old QGIS 2.2.0 Valmiera.
if you are using ESRI products. here is the code to convert hdf to geotiff, mosaic and then clip .
To have a better view of what you want, as it is a more punctual phenomenon, you can use the MOD13Q1 that has the same temporality but the spatial resolution is 250m, providing better precision to the project. You can extract the NDVI of the product MOD13Q1 and work it in tiff format that is a more friendly format for processing of satellite images
