Deck 15: Spatial Interpolation

Question 1

A larger band width used in kernel density estimation will result in a smoother surface.

Answer 1

True

Question 2

A larger sample size will always produce more accurate estimations using the IDW method.

Answer 2

False

Question 3

The root-mean-square (RMS) error is commonly used for selecting an optimal interpolation method. What does the RMS error measure in spatial interpolation?

Answer 3

No Answer

Question 4

Both IDW and kriging use weights in estimating an unknown value. Describe the difference between the two interpolation methods in terms of how these weights are derived.

Question 5

A higher power for the IDW method means that:

A) Closer control points will have greater influence on the estimation.
B) Control points will be equalized in terms of their influence on the estimation.
C) Closer control points will have less influence on the estimation.

Question 6

Which of the following is a global interpolation method?

A) none of these is correct
B) inverse distance weighted
C) thin-plate splines
D) trend surface analysis
E) kriging

Question 7

Describe in general terms how cell densities are derived using the kernel density estimation method.

Question 8

Define "spatial interpolation."

Question 9

If the sampled points are spatially correlated in kriging, then one would expect a(n) _____ in the semivariance with an increase in the distance between sampled points.

A) increase
B) decrease

Question 10

A better spatial interpolation method should have a _____ RMS error.

A) lower
B) higher

Question 11

A higher-order trend surface model can generally better approximate a more complex surface.

Question 12

Describe how a cross-validation analysis is performed.

Question 13

Which of the following is true about thin-plate splines for spatial interpolation?

A) All of these are correct
B) Both the thin-plate splines method produces a minimum-curvature surface and and smooth isolines.
C) The thin-plate splines method tends to produce steep gradients (overshoots) in data-poor areas.
D) The thin-plate splines method produces a minimum-curvature surface.
E) The thin-plate splines method produces smooth isolines.

Question 14

How does universal kriging differ from ordinary kriging?

Question 15

Which of the following is not true about the inverse distance weighted (IDW) method?

A) IDW tends to produce small, enclosed isolines.
B) The predicted values from IDW are always within the range of maximum and minimum values of the known points.
C) IDW is a local interpolation method.
D) None of these is correct

Question 16

What is an exact interpolation method?

Question 17

Binning is a process for creating a usable semivariogram from empirical data. Describe how binning is performed.

Question 18

Anisotropy means the absence of directional differences in spatial dependence.

Question 19

Which kriging method allows the use of one or more secondary variables?

A) block kriging
B) disjunctive kriging
C) cokriging
D) indicator kriging

Question 20

Describe in general terms how Thiessen polygons are derived.

Question 21

Illustrate the difference between the closest point sampling method and the quadrant sampling method by using a sample size of 12.

Question 22

The accuracy of spatial interpolation can be influenced by:

A) number of control points
B) all of these are correct
C) data-poor areas
D) distribution of control points

Question 23

Explain the difference between global and local interpolation methods.

Question 24

Define the elements of nugget, range, and sill in a semivariogram.

Question 25

Which of the following will typically result in a smooth interpolated surface?

A) thin-plate splines
B) kriging
C) IDW

Question 26

Describe how the semivariance can be used to quantify the spatial dependence in a data set.

Question 27

What are the required inputs for spatial interpolation?

Question 28

A semivariogram must be fitted with a mathematical model before it can be used in kriging. Why?

Question 29

Which of the following is a stochastic interpolation method?

A) inverse distance weighted
B) Thiessen polygons
C) thin-plate splines
D) kriging
E) none of these is correct

Question 30

Which of the following is true about Thiessen polygons?

A) Thiessen polygons do not vary in size.
B) Thiessen polygons are smaller in areas with denser control points.
C) The derivation of Thiessen polygons is based on a global method.
D) The derivation of Thiessen polygons is based on a mathematical model.