# Problematic Reflectance map for the Red channel

**URL:** <https://community.pix4d.com/t/problematic-reflectance-map-for-the-red-channel/21871>\
**Category:** Agriculture\
**Created:** [March 17, 2022, 8:59am UTC](https://community.pix4d.com/t/problematic-reflectance-map-for-the-red-channel/21871 "2022-03-17T08:59:53Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Paulina\_Raeva](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/paulina_raeva/32/382_2.png) [@Paulina\_Raeva](https://community.pix4d.com/u/Paulina_Raeva)\
**Post date:** [March 17, 2022, 8:59am UTC](https://community.pix4d.com/t/problematic-reflectance-map-for-the-red-channel/21871/1 "2022-03-17T08:59:53Z")

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Dear support,  
I am using the multiSPEC 4c and I have one problematic dataset where the red reflectance map gives very strange values, resp. I can’t compute the NDVI. I am attaching a printscreent.  
Thank you for your help!

 ![NDVI](https://global.discourse-cdn.com/pix4d/original/2X/6/6e6900e4b6defade313cfdf20c92304df71da072.jpeg)

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**Author:** ![Jose.Arnaudo](https://sea2.discourse-cdn.com/pix4d/user_avatar/community.pix4d.com/jose.arnaudo/32/5966_2.png) [@Jose.Arnaudo](https://community.pix4d.com/u/Jose.Arnaudo)\
**Post date:** [March 17, 2022, 10:12am UTC](https://community.pix4d.com/t/problematic-reflectance-map-for-the-red-channel/21871/2 "2022-03-17T10:12:04Z")

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Hi,

The values of the reflectance map will lie between 0-1 only when a radiometric target is used. Are you using a target? If yes, it also might be that the target is overexposed/underexposed and the values were not used for radiometric calibration.