Hi!

My first guess is, that the output layer type is not set to 32bit float?!

Cheers,

Matthias

Thanks for your answer, but this was not the problem. I have done this.

I can calculate plus and subtract the different layers, but as soon i want to divide them, it doesn't work.

I think the problem are the orthofotos. With Sentinel-data it works.

greets

It may be that everything was calculated correctly and only the display needs to be adjusted. Please set Image Layer Equalization range from -1 to 1 (for help, please check View Setting dialog). Does it make sense now? Which values are displayed when MouseOver pixels?

That was the problem! Thank you very much!
Kind regards

The reason for the problem is that at least for one pixel the sum of RED and NIR equals 0 and when calculating the NDVI here a value is divided by 0 which is mathematically undefined and results by eCognition with the highest possible output value (depending on the layer type).

You could set all NDVI values greater than 1 to -1 in a second step using 'layer arithmetics'.

Or you could use the algorithm 'index layer calculation' where the 'undefined value' is set as parameter. As you can see, there are many ways to solve the problem in eCognition.