W8

Question 1

What is Spatial interpolation?

Answer 1

The procedure of predicting values at un-sampled locations based on some existing within the same area of interest
- could be used to derive a continuous surface of the measured attribute
- interpolation can also be used to fill data gaps in a grid

Question 2

How does spatial interpolation work?

Answer 2

A mathematical model is used estimate the values of the missing locations

Question 3

What is tobler’s law

Answer 3

Everything is related to everything else, but closer things are more related
- this is the most fundamental “law” in the discipline of geography

Question 4

How does Tobler’s law related to interpolation?

Answer 4

It depends on a property known as spatial autocorrection, a metric that quantifies the degree to which near and more distant things are related
- makes spatial distributions easier to model with distance becoming the key attribute

Question 5

Explain the distinction between exact and inexact interpolations.

Answer 5

Exact: interpolated surface passes through all original data points (reproduces data values)
Inexact: does not pass through all data points (does not reproduce data values)

Question 6

Explain the distinction between global and local interpolation

Answer 6

Global: estimated value is a function of all the values in the data set (usually based in statistics)
Local: estimated value is a function of a subset of values within the vicinity of the unknown value (like Tobler said)

Question 7

What are the two global methods

Answer 7

1. Classification (inexact)
2. Trend surfaces (inexact)