Hi,

While plotting the semivariogram, we generally take the expectation of the semivariance values of each lag and then plot it (literally we will have one point per lag) ! but why do Geostatistical analyst plots many points in each lag? Also the lag distance along x axis has 10^-ve values (example h.10^-3). Is this correct? can somebody clarify this?

Thanks

Deep

While plotting the semivariogram, we generally take the expectation of the semivariance values of each lag and then plot it (literally we will have one point per lag) ! but why do Geostatistical analyst plots many points in each lag? Also the lag distance along x axis has 10^-ve values (example h.10^-3). Is this correct? can somebody clarify this?

Thanks

Deep

The Wizard help describes the points as:

"Binned points (the red dots) are generated by grouping (binning) empirical semivariogram/covariance points together using square cells that are one lag wide. Average points (the blue crosses, which are new in ArcGIS 10) are generated by binning empirical semivariogram/covariance points that fall within angular sectors. The graph can display binned points, average points, or both. Binned points show local variation in the semivariogram/covariance values, whereas average values show smooth semivariogram/covariance value variation."

As for the h.10^-5 on x axis, it is using the formula: x = h(10^-5). Scientific notation often takes the form h = x(10^5). The difference is whether you are writing the scale relative to h or relative to the value on the x-axis. We chose this way because that is historically how the scale of the semivariogram is written.

If you require further information or clarification, let me know. I've attached an image of a typical semivariogram from the Geostatistical Wizard in ArcGIS 10.