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National Recreation Model

Hi Guys, 

I noticed when doing an assessment of recreation value that you can end up with a single area with extremely high PUDs that corresponds to the lat/long Google places for an something. In my case, the Google lat/long for a country. In Namibia this happened to be placed in the middle of no-where so was easy to pick up and because of low densities of photos, the assumption to remove all of them seemed appropriate. This could potentially be a problem for other areas, where it is uncertain what proportion of the number is due to this vs. actual photos taken.

Any thoughts on how to avoid this in future?



Comments

  • DaveDave Member, Administrator, NatCap Staff
    Hi KatForsythe,

    I've noticed this problem in at at least one instance, working at a national scale where there was one cell with very large PUD, many times larger than the next highest value, and seemingly no point of interest at that location. I took a similar approach to you and replaced that cell's value with the average of all of it's neighbouring cells. There is no way to handle this inside of the InVEST model, but you can take the results into GIS or other statistical software to adjust values and continue modeling.

    Thanks for raising the issue, it's an important reminder to look critically at model results.

  • RichRich Administrator, NatCap Staff
    Hi Dave, I remember talking about this when we were first setting up the model.  If I remember right, on one hand we could find a lot of these country level points in the dataset and remove them, but on the other hand they still might be useful as data if aggregated to a high enough level, right?

    Anyway, wanted to let you know that if it did make sense, we could remove them in the future if this were more of a burden than a boon.
  • DaveDave Member, Administrator, NatCap Staff
    Yeah that's a good point, Rich. Those points could certainly be useful depending on the scale of analysis. The country-level points may be a burden more often than a boon, but that's anecdotal. And I think there are likely also 'state-level' / 'province-level' / 'island-level' points that are analogous.
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