1

I have created a NDVI image from Landsat 7 data using ERDAS (veg_NDVI.gmd). This model was already in ERDAS 9.3. After creation the final output visually highlighting vegetative areas but the value showing 0-255. But theoretically it is known that the NDVI value ranges from (-1) to (+1). Please let me be clear about this confusion and suggest the right way.

1

Erdas provides an option to stretch the NDVI values from the typical floating point NDVI range (-1 to 1) to 8-bit unsigned integer (0 - 255). This can be handy to reduce file size from floating point to 8-bit unsigned integer (0 - 255) and stretch the values to the full pixel depth of the image. However, it also reduces the sensitivity of the index. You can create NDVI doing the following: Interpreter > Spectral Enhancement > Indices. In this dialogue box, make sure to not select "Stretch to Unsigned 8-bit". There is also a you tube video that can walk you through the process.

enter image description here

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.