# SWY L outputs negative values or no significant

**URL:** <https://community.naturalcapitalalliance.org/t/swy-l-outputs-negative-values-or-no-significant/3671>\
**Category:** Software Support\
**Tags:** seasonal-water-yield\
**Created:** [April 23, 2023, 11:44pm UTC](https://community.naturalcapitalalliance.org/t/swy-l-outputs-negative-values-or-no-significant/3671 "2023-04-23T23:44:14Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![SofiaEscotoH](https://yyz1.discourse-cdn.com/flex031/user_avatar/community.naturalcapitalalliance.org/sofiaescotoh/32/2516_2.png) [@SofiaEscotoH](https://community.naturalcapitalalliance.org/u/SofiaEscotoH)\
**Post date:** [April 23, 2023, 11:44pm UTC](https://community.naturalcapitalalliance.org/t/swy-l-outputs-negative-values-or-no-significant/3671/1 "2023-04-23T23:44:14Z")

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I am getting very large negative values ​​at the L outputs. Can it be related with high evotranspiration values? I’ve checked on the forum, somebody had a similar doubt, the answer point to check if the negative values were significant, and in my case, negative values can reach -1632.41 value on L output and no significan value on L\_sum (you can see it on the image attached)

Is it “normal” to see gridded outputs?

 ![image](https://canada1.discourse-cdn.com/flex031/uploads/naturalcapitalproject/original/2X/0/06ce31d17cc87f1d2f624ae976be3d889818137b.jpeg)

[InVEST-natcap.invest.seasonal\_water\_yield.seasonal\_water\_yield-log-2023-04-23–15\_19\_25.txt](https://community.naturalcapitalalliance.org/uploads/short-url/kaqqzaOJ7x1QzXGMiahcgAWslhs.txt) (42.5 KB)

Thanks in advance

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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:** [April 24, 2023, 3:24pm UTC](https://community.naturalcapitalalliance.org/t/swy-l-outputs-negative-values-or-no-significant/3671/2 "2023-04-24T15:24:18Z")

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Hi @SofiaEscotoH -

I’m not sure about the L values, but the grid pattern may be caused by using a “nearest neighbor” interpolation method on your DEM when you reprojected/resampled/etc to prepare it. “Bilinear”, “Cubic” and probably other interpolation methods do not produce this grid.

~ Stacie

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**Author:** ![jdouglass](https://yyz1.discourse-cdn.com/flex031/user_avatar/community.naturalcapitalalliance.org/jdouglass/32/9_2.png) [@jdouglass](https://community.naturalcapitalalliance.org/u/jdouglass)\
**Post date:** [April 24, 2023, 11:23pm UTC](https://community.naturalcapitalalliance.org/t/swy-l-outputs-negative-values-or-no-significant/3671/3 "2023-04-24T23:23:07Z")

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The very negative values in that upper section of the raster might be caused by the model not correctly handling nodata values from precipitation, quickflow or AET. Could you check those model outputs and see if any of them have nodata values where we’re seeing negative pixel values in L?

Thanks!  
James

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**Author:** ![system](https://canada1.discourse-cdn.com/flex031/uploads/naturalcapitalproject/original/2X/8/8d95591aa074da87ea0fdd61ca47c1c3c0588aa7.png) [@system](https://community.naturalcapitalalliance.org/u/system)\
**Post date:** [July 23, 2023, 11:23pm UTC](https://community.naturalcapitalalliance.org/t/swy-l-outputs-negative-values-or-no-significant/3671/4 "2023-07-23T23:23:24Z")

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Closed on July 23, 2023, 11:23pm UTC

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