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.