# Wrong output in NDR model

**URL:** <https://community.naturalcapitalalliance.org/t/wrong-output-in-ndr-model/2957>\
**Category:** Software Support\
**Tags:** ndr\
**Created:** [July 29, 2022, 2:09pm UTC](https://community.naturalcapitalalliance.org/t/wrong-output-in-ndr-model/2957 "2022-07-29T14:09:14Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![umr](https://avatars.discourse-cdn.com/v4/letter/u/58f4c7/32.png) [@umr](https://community.naturalcapitalalliance.org/u/umr)\
**Post date:** [July 29, 2022, 2:09pm UTC](https://community.naturalcapitalalliance.org/t/wrong-output-in-ndr-model/2957/1 "2022-07-29T14:09:14Z")

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#### hi,I used the NDR model to get an error output, how do I solve it.Thank you！

 ![error](https://canada1.discourse-cdn.com/flex031/uploads/naturalcapitalproject/original/2X/e/e6bb648f6afe24c4329116ebb43734544144e416.png)

### Log file

[InVEST-natcap.invest.ndr.ndr-log-2022-07-29–21\_46\_25.txt](https://community.naturalcapitalalliance.org/uploads/short-url/sJRzwUT4dCqIeDm8psehupONOxj.txt) (33.7 KB)

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**Author:** ![swolny](https://yyz1.discourse-cdn.com/flex031/user_avatar/community.naturalcapitalalliance.org/swolny/32/181_2.png) [@swolny](https://community.naturalcapitalalliance.org/u/swolny)\
**Post date:** [August 1, 2022, 3:03pm UTC](https://community.naturalcapitalalliance.org/t/wrong-output-in-ndr-model/2957/2 "2022-08-01T15:03:14Z")

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Hi @umr, and welcome to the forum!

Do any of the other raster outputs have these error values, or is it only n\_subsurface\_export?

~ Stacie

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**Author:** ![umr](https://avatars.discourse-cdn.com/v4/letter/u/58f4c7/32.png) [@umr](https://community.naturalcapitalalliance.org/u/umr)\
**Post date:** [August 2, 2022, 11:52am UTC](https://community.naturalcapitalalliance.org/t/wrong-output-in-ndr-model/2957/3 "2022-08-02T11:52:22Z")

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Hi Stacie!  
Yes, maybe it’s the different raster data projection caused abnormal output. After reprojection, NDR works in right way.  
But there is another problem, I use NDR calculate n\_export for 3 years, one of them is normal, the other two contain some negative value(eg -0.3). The input data were processed together. I’m trying to find out what caused it.

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<div class="post-metadata">

**Author:** ![swolny](https://yyz1.discourse-cdn.com/flex031/user_avatar/community.naturalcapitalalliance.org/swolny/32/181_2.png) [@swolny](https://community.naturalcapitalalliance.org/u/swolny)\
**Post date:** [August 2, 2022, 7:26pm UTC](https://community.naturalcapitalalliance.org/t/wrong-output-in-ndr-model/2957/4 "2022-08-02T19:26:29Z")

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Interesting that the projection caused that output, thanks for letting us know. Can you tell us which projection the data was in originally, and what you reprojected it to?

One way of troubleshooting the model output is to look at the files in the _[Workspace]\intermediate\_outputs_ folder, and see how they correspond with the equations in the User Guide. When you identify the output where the negative values first begin, it might help you understand why they’re happening. Let us know what you find.

~ Stacie