Very well explained by Reuben Reyes

Dear Dewan Salman Sunny ,

Terra and Aqua are two satellites, both equipped of Earth observation instruments, including MODIS (Moderate-Resolution Imaging Spectroradiometer).

Terra and Aqua are slightly different:

- Terra was launch in 1999 and is equipped of 5 instruments (MODIS, ASTER, CERES, MISR, MOPITT).

- Aqua was launch in 2002 and is equipped of 6 instruments (MODIS, AIRS, AMSU-A, HSB, CERES, AMSR-E).

Both satellites are equipped with the same MODIS instrument, which takes pictures of Earth in 36 spectral bands. So when you download products from MODIS Terra or MODIS Aqua, they are identical. The only difference is the acquisition date in years - since 1999 for Terra, since 2002 for Aqua - and days - Terra crosses the equator from north to south at approximately 10:30 A.M. local time, 1:30 P.M. local time for Aqua.

According your other question, I think using 4 spectrals bands is enough. You can produce land cover maps with band 1 (Red), band 2 (Near Infrared), band 3 (Blue), band 4 (Green). You can also include bands 5 and 6 (SWIR) to get better results on water extraction. However, don't forget that MODIS resolution is quiet low (250 m to 1 km). So if you want accurate results in a local place, you can use other open source images such as LANDSAT (30 x 30m) or Sentinel 2 (10 x 10 m).

I hope it helps you,

Rémi DM

Hope this helps, here is a link Terra vs. Aqua :

https://nsidc.org/data/modis/terra_aqua_differences

Rémi De Matos-Machado , Thank you so much for your opinion sir. It covered my all queries.

Reuben Reyes Thank you very much sir. The article is helpful.

Rémi De Matos-Machado I am using Erdas Imagine 2014, I have downloaded a MODIS surface reflectance product from Earthdata.nasa . I got a single .hdf file. How can I get the individual spectral bands (1 - 6) ?

Dewan Salman Sunny,

I am not familiar with Erdas.

However, you can use other softwares to open it. It works with:

- QGIS (using "semi-automatic classification plugin" after downloading it). QGIS is free.

- ArcGIS (using "extract subdataset" tool).

- Python (using "pyhdf" library). Python is free.

The hdf file contains 12 files. But only 2 subdatasets have to be used for your task (subdataset number 9 and 10).

Also, note that spatial resolution differs from a band to another. Resolution is 250 m for bands 1-2, 500 m for bands 3-7 and 1 km for bands 8-36. If you want to apply the resolution of bands 1-2 to bands 3-7, you can use pan-sharpening methods (panchromatic is not available but you can use other bands).

Rémi

Rémi De Matos-Machado Can you provide me any tutorial working with MODIS surface reflectance prooduct for image classification? Thank you in advance.

Dear Dewan,

Both the terra and aqua products are same, usually people used to combine these two to do the analyses since 1999.

You may have a look at these links,

https://www.hindawi.com/journals/amete/2015/424291/

https://modis-land.gsfc.nasa.gov/pdf/MOD09_UserGuide_v1.4.pdf

Best

Depend on your interest:

For Land: Terra

and Ocean: Aqua

You ask mutiple questions, First you should decided, what are your objectives, if you want landcover class, you can download MCD12Q1 landcover class, Aqua defined Water/Oceans/sea and Terra mean Land/Dry area. If you need more asnwers from me, you can follow me at research gate.

Terra for land and Aqua for ocean are two satellites, both equipped of Earth observation instruments, including MODIS (Moderate-Resolution Imaging Spectroradiometer).