When trying to smooth spatial data, I found this very helpful tutorial regional smoothing.
There are two steps to estimate a "smoothed" value for a geographical point:
- Finding K nearest neighbors
- Calculate the local G statistics
My initial idea was only to calculate the average value with the KNN, to smooth the data across the geographical zone. But from this article, I also discovered Gettis-Ord statistic/local G statistic with the
localG function. The author indicated that it can also smooth the spatial data.
But the locla G statistic is a zero centered variable, and the value can not directly represent an estimation of the initial variable.
Is it possible to use local G statistics to really "smooth" the data and,if so, then how?
In this example of local G official documentation of the spdep package, we can see that initial values (xyz$val) are between 30 and 120, and the g statistic value are between -5 and 5.