Deck 13: Terrain Mapping and Analysis

Question 1

Using the same input data, one can always derive the same slope layer from different GIS packages.

Answer 1

False

Question 2

A percent slope layer cannot have values greater than 100 percent.

Answer 2

False

Question 3

Define "breaklines" in the construction of a TIN.

Answer 3

No Answer

Question 4

Which of the following parameters represents the angle measured from the horizon to the altitude of the observer in a 3-D view?

A) none of these is correct
B) viewing azimuth
C) viewing angle
D) viewing distance

Question 5

ArcGIS can derive a slope layer in either percent slope or degree slope.

Question 6

Define "slope" and "aspect" as measures of the land surface.

Question 7

Explain the difference between a DEM and a DSM.

Question 8

Which of the following ArcGIS extensions works with TINs?

A) 3D Analyst
B) Spatial Analyst
C) Geostatistical Analyst

Question 9

ArcGIS uses the maximumz-tolerance algorithm to convert a DEM into a TIN. Explain how the algorithm works.

Question 10

Aspect readings can range from:

A) 0 to 90 degrees
B) 0 to 100 degrees
C) 0 to 360 degrees
D) 0 to 180 degrees

Question 11

Describe factors that can influence the accuracy of slope and aspect measures from a DEM.

Question 12

What is 3-D draping?

Question 13

Contour lines cannot intersect one another.

Question 14

Suppose you are given a DEM to make a contour map. The elevation readings in the DEM range from 856 to 1324 meters. If you were to use 900 as the base contour and 100 as the contour intervals, what contour values would appear on the map?

Question 15

The operation of deriving slope and aspect from an elevation raster is commonly called a neighborhood operation. Why?

Question 16

A hillshade map would look _____ if the sun's angle were higher:

A) darker
B) the same
C) lighter

Question 17

Z-scale in a 3-D view represents the ratio of:

A) the vertical scale / the horizontal scale
B) the horizontal scale / the vertical scale

Question 18

Different computing algorithms are available for deriving slopes from an elevation raster. Summarize in words (not equations) their major differences.

Question 19

Which of the following statements is true about DEMs and TINs?

A) One can only convert a TIN into a DEM.
B) None of these are correct.
C) One can convert a DEM into a TIN, or a TIN into a DEM.
D) One can only convert a DEM into a TIN.

Question 20

What assumptions are used in creating a TIN?

Question 21

Describe factors that can influence the visual effect of hill shading.

Question 22

The local illumination condition in a hillshade view can be influenced by

A) all of these are correct
B) local slope
C) local aspect
D) sun's angle

Question 23

The accuracy of slope measures from a DEM can be influenced by

A) local topography
B) the computing algorithm
C) all of these are correct
D) both the computing algorithm and the DEM resolution
E) the DEM resolution

Question 24

Which of the following parameters represents the direction from the observer to the surface in a 3-D view?

A) viewing distance
B) Z-scale
C) viewing azimuth
D) viewing angle

Question 25

Describe the four parameters that can change the appearance of a 3-D view.

Question 26

List by point, line, and area the types of data that one can use to create and modify a TIN.

Question 27

What is a TIN?

Question 28

A positive curvature value means an upwardly _____ surface and a negative curvature value means an upwardly ______ surface:

A) concave, convex
B) convex, concave

Question 29

Define "profile curvature" and "plan curvature."

Question 30

Deriving slope and aspect from an elevation raster is a ______ operation:

A) zonal
B) local
C) global
D) neighborhood