Deck 6: Geometric Transformation

Question 1

Which resampling method usually results in the smoothest output?

A) cubic convolution
B) nearest neighbor
C) bilinear interpolation

Answer 1

cubic convolution

Question 2

Operationally, the affine transformation of a satellite image involves three sequential steps. What are these steps?

Answer 2

No Answer

Question 3

Explain image-to-map transformation.

Answer 3

No Answer

Question 4

What are the actual and estimated coordinates of the ground control points in an image-to-map transformation?

Question 5

How does one obtain ground control points (GCPs) for geometric transformation of a satellite image?

A) GCPs are selected from the satellite image.
B) GCPs are already identified in the satellite image.
C) GCPs are available in a GIS.

Question 6

A geometric transformation of a newly digitized map normally requires a minimum of ____ control points:

A) 4
B) 6
C) 2
D) 1

Question 7

A USGS 1:24,000 scale quadrangle map has ___ points with known longitude and latitude values that can be used as control points for geometric transformation:

A) 8
B) 12
C) 4
D) 16

Question 8

In ArcMap, the resampling of pixel values is included as part of the rectification process.

Question 9

Which resampling method is recommended for resampling categorical data?

A) cubic convolution
B) bilinear interpolation
C) nearest neighbor

Question 10

Mathematically, the affine transformation uses a pair of:

A) second-order polynomial equations
B) third- or higher-order polynomial equations
C) first-order polynomial equations

Question 11

Define the "root-mean-square (RMS) error" in geometric transformation.

Question 12

Which transformation method is most commonly used in GIS?

A) Affine transformation
B) projective transformation
C) Similarity transformation
D) Equiarea transformation

Question 13

What is pyramiding?

Question 14

Which resampling method is most complex computationally?

A) bilinear interpolation
B) nearest neighbor
C) cubic convolution

Question 15

Why do we have to perform the resampling of pixel values following an image-to-map transformation?

Question 16

What are the actual and estimated coordinates of the control points in a map-to-map transformation?

Question 17

Geometric transformation is typically an iterative process. Why?

Question 18

You have digitized a layer from a USGS 7.5-minute quadrangle map including the four corner tics of the map with known longitude and latitude values. Describe the steps you will follow to transform the digitized layer into UTM coordinates.

Question 19

Describe a scenario, in which the RMS error may not be a reliable indicator of the goodness of a map-to-map transformation.

Question 20

The affine transformation allows rotation, translation, skew, and differential scaling. Describe what differential scaling does.

Question 21

A link table used in ArcMap for georeferencing shows X Source, Y Source, X Map, and Y Map. Which pair represents the estimated location of the control point?

A) X Map and Y Source
B) X Source and Y Map
C) X Map and Y Map
D) X Source and Y Source

Question 22

Which transformation method is usually recommended for aerial photograph-to-map transformation?

A) Similarity
B) Affine
C) Projective
D) Equiarea

Question 23

Why is geometric transformation important in GIS?