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I'm working on NDVI data from MODIS_13Q1 product. As far as I know, NDVI data has scale and offset values. I used these values to get geophysical values of pixels.

My problem is after processing these data (linear interpolation and spline fitting missing values), the value of pixels is float, not integer as original data, and the size of processed datasets when saved is huge (from 100 MB to 700-800 MB). How can I use scale and offset values to convert value of pixels back to integer, and does it cause losing data?

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The scale factor for the MOD13Q1 NDVI product is 0.0001. There is no offset.

To convert back to integer, divide by 0.0001 and save the result as a 16bit signed integer type.

  • In order to scale the MOD13Q1 NDVI data you need to multiply the downloaded image with 0.0001. This won't cause any data loss. When you scale the MOD13Q1 NDVI data, which has integer values between -2000 and 10000, the bit type will become floating. 16 bit signed integer is the bit type of the downloaded MOD13Q1 image. – Ayda Aktas Mar 4 '17 at 23:01

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