# Problem interpreting quality and degradation in habitat quality model **URL:** \ **Category:** Software Support\ **Tags:** habitat-quality\ **Created:** [September 23, 2023, 1:23pm UTC](https://community.naturalcapitalalliance.org/t/problem-interpreting-quality-and-degradation-in-habitat-quality-model/4106 "2023-09-23T13:23:01Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Eshetu](https://avatars.discourse-cdn.com/v4/letter/e/22d042/32.png) [@Eshetu](https://community.naturalcapitalalliance.org/u/Eshetu)\ **Post date:** [September 23, 2023, 1:23pm UTC](https://community.naturalcapitalalliance.org/t/problem-interpreting-quality-and-degradation-in-habitat-quality-model/4106/1 "2023-09-23T13:23:01Z")
Dear Sir, I am very happy if you clarify my doubts regarding habitat quality model: \*First, I initially run habitat quality using the default **Half-saturation Constant** (0.05) to see the highest grid-cell degradation level. However, the “quality” image and Deg\_sum image shows the reverse as compared to the real habitat quality. The value of “quality” image was highest in crop land and urban area but very low in forest land. Could you clarify why? After I set **Half-saturation Constant 0.5 (i.e., 0.9/2), the quality image looks good as I evaluated it based on known habitat locations on the ground.** _Second, the habitat quality result creates a kind of circular feature around the urban area, similar to point interpolation. The radius of the circle was the same as the maximum distance I put in the CSV file. Can I avoid circular visualization?_\* \*Third, could you clarify the importance of output images in the “intermediate” folder? Thank you so much for your time and kindness ! ---
**Author:** ![dave](https://yyz1.discourse-cdn.com/flex031/user_avatar/community.naturalcapitalalliance.org/dave/32/70_2.png) [@dave](https://community.naturalcapitalalliance.org/u/dave)\ **Post date:** [October 3, 2023, 12:41pm UTC](https://community.naturalcapitalalliance.org/t/problem-interpreting-quality-and-degradation-in-habitat-quality-model/4106/2 "2023-10-03T12:41:22Z")
Hi @Eshetu , thank you for your questions, sorry for the delayed response. Which version of InVEST are you using? Can you please share the log file from the output workspace? This model had some significant changes added in version 3.13.0, specifically related to the distance decay functions. The changes are described as follows, > The model now uses an euclidean distance implementation for decaying > threat rasters both linearly and exponentially. Since InVEST 3.3.0 a > convolution implementation has been used, which reflected how > the density of a threat or surrounding threat pixels could have an > even greater, cumulative impact and degradation over space. However, this > was never properly documented in the User’s Guide and is not the approach > taken in the publication. The convolution implementation also produced > degradation and quality outputs that were difficult to interpret. Could you please try the latest version and let us know if the results make more sense? [https://naturalcapitalproject.stanford.edu/software/invest/invest-dowloads-data](https://naturalcapitalproject.stanford.edu/software/invest/invest-dowloads-data) Thank you, ---
**Author:** ![Eshetu](https://avatars.discourse-cdn.com/v4/letter/e/22d042/32.png) [@Eshetu](https://community.naturalcapitalalliance.org/u/Eshetu)\ **Post date:** [October 3, 2023, 1:30pm UTC](https://community.naturalcapitalalliance.org/t/problem-interpreting-quality-and-degradation-in-habitat-quality-model/4106/3 "2023-10-03T13:30:31Z")
Dear Prof. Dave, thank you so much for your reply. Attached herewith is the log file from the output workspace. I used **version** **3.13.0**. What still persists is a circular feature around the urban area in habitat quality output, similar to interpolation mapping. The remaining questions were resolved. I am looking forward to hearing from you! _ **Warm Regards !** _ [InVEST-natcap.invest.habitat\_quality-log-2023-09-23–20\_32\_58.txt](https://community.naturalcapitalalliance.org/uploads/short-url/oJPSUVZLFyXNAHPPuGRBqjck6sE.txt) (15.5 KB) ---
**Author:** ![dave](https://yyz1.discourse-cdn.com/flex031/user_avatar/community.naturalcapitalalliance.org/dave/32/70_2.png) [@dave](https://community.naturalcapitalalliance.org/u/dave)\ **Post date:** [October 4, 2023, 5:40pm UTC](https://community.naturalcapitalalliance.org/t/problem-interpreting-quality-and-degradation-in-habitat-quality-model/4106/4 "2023-10-04T17:40:45Z")
Hi @Eshetu , it sounds like upgrading to version 3.13.0 solved some of the problems, that’s good! > [@Eshetu](#): > > What still persists is a circular feature around the urban area in habitat quality output, similar to interpolation mapping. I can’t say for sure without seeing this, but this circular feature sounds like an expected outcome. The model is using a distance decay function to map the impact of a threat on the surrounding landscape. The impact will be greatest near to the threat, and then less as distance increases in all directions, forming a roughly circular impact zone. Does that agree with the quality results you see? ---
**Author:** ![Eshetu](https://avatars.discourse-cdn.com/v4/letter/e/22d042/32.png) [@Eshetu](https://community.naturalcapitalalliance.org/u/Eshetu)\ **Post date:** [October 8, 2023, 1:40pm UTC](https://community.naturalcapitalalliance.org/t/problem-interpreting-quality-and-degradation-in-habitat-quality-model/4106/5 "2023-10-08T13:40:31Z")
yes, my result is the same as what you stated. Thank you for your reply. ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex031/uploads/naturalcapitalproject/original/2X/8/8d95591aa074da87ea0fdd61ca47c1c3c0588aa7.png) [@system](https://community.naturalcapitalalliance.org/u/system)\ **Post date:** [October 15, 2023, 1:40pm UTC](https://community.naturalcapitalalliance.org/t/problem-interpreting-quality-and-degradation-in-habitat-quality-model/4106/6 "2023-10-15T13:40:36Z")
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