Sample size

Most interpolation methods allow you to control the number of sample points used to estimate cell values. For example, if you limit your sample to five points, the interpolator will use the five nearest points to estimate cell values.

The distance to each sample point will vary depending on the distribution of the points. If you have a lot of sample points, reducing the size of the sample you use will speed up the interpolation process because a smaller set of numbers will be used to estimate each cell value.

When the sample size is limited to five sample points, as in this case, only the five nearest points are used in the calculation of the estimated cell value. All other points are disregarded.

You can also control your sample size by defining a search radius. The number of sample points found within a search radius can vary depending on how the points are distributed. You can choose to use some or all of the samples that fall within this radius to calculate the cell value. A variable search radius will continue to expand until the specified sample size is found. A fixed search radius will use only the samples contained within it, regardless of how many or how few that might be.

If the search radius in this sample were fixed, only the values of the sample points within the radius would be used to calculate the estimated cell value. If the search radius were variable and the minimum sample size were 8, the search radius would expand until it contained eight sample points.