[Qgis-user] Question about Weighting Power value when running Grid-Inverse Distance to a Power

[J.O.Williams]

A power of 1 is a linear interpolation among all points in the search 
radius.


A power of 2 causes the "closest point" in the search radius to have a 
slightly higher weight.


A power of 4, 6 and especially 10 causes the closest point to behave 
like a polygonal or  theissen polygon.


A power of 0.5 causes the farther away points to have a larger influence 
than closer points....


The equations used only depend on the distance the points are from each 
other.  NOT the value of any of the points.  Though David has a section 
on how the variogram can be applied to IDS.


All the power IDS theory (if there is one) came out of the mining 
industry in the early 1960's because it was simple.


Hope this helps.

J.O. Williams


On 9/17/19 4:00 AM, Daniel Zepeda Rivas wrote:
>
> When using the Raster -> Analysis -> Grid (Inverse Distance to a Power)
>
> At the menu just before pressing run, can somebody please explain me 
> the effect of the "Weighting power" option in the interpolation process?
>
> I'm trying to make a temperature map based on points representing each 
> weather station, containing the yearly averages values of temperature, 
> and when moving the number from the 2 (set it by default) to 4, 6 or 
> 10, the map changes significantly
>
>
>
> _______________________________________________
> Qgis-user mailing list
> Qgis-user at lists.osgeo.org
> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/20190917/74f2ca52/attachment.html>