Deck 7: Spatial Data Accuracy and Quality

Question 1

Explain the purpose of edgematching.

Answer 1

No Answer

Question 2

Which of the coverage's topological relationships does an overshoot violate?

A) area definition
B) connectivity
C) contiguity

Answer 2

connectivity

Question 3

A node that breaks a continuous line into separate line segments is called an:

A) dangling node
B) overshoot
C) undershoot
D) pseudo node

Answer 3

pseudo node

Question 4

The Douglas-Peucker algorithm is used for:

A) line densification
B) line reshaping
C) line smoothing
D) line generalization

Question 5

A digitized map from a secondary data source such as a USGS quadrangle map is subject to more location errors than a primary data source. Why?

Question 6

Suppose a point location is recorded as (575729.0, 5228382) in data set 1 and (575729.643, 5228382.119) in data set 2. Which data set has a higher data precision?

A) Data set 2
B) Data set 1

Question 7

The geodatabase has more than 30 topology rules for point, line, and polygon features.

Question 8

Which of the following can be a source of location errors?

A) errors in scanning and tracing
B) human errors in manual digitizing
C) both human errors in manual digitizing and errors in scanning and tracing
D) errors from geometric transformation
E) all of these are correct

Question 9

Line smoothing is the process of reshaping lines by using splines or some other mathematical functions.

Question 10

Which of the following operations can be accomplished by non-topological editing?

A) union features
B) all of the above
C) only merge features and union features
D) buffer features
E) merge features

Question 11

Define "location errors."

Question 12

Topology rules in ArcGIS can only be applied to feature classes in a feature dataset.

Question 13

Give an example of a polygon feature class that can benefit from the topology (polygon) rule of "Must be covered by feature class of"?

Question 14

Some nontopological editing operations can create features from existing features. Give two examples of such operations.

Question 15

Map topology in ArcGIS mainly works with coincident lines between features. What does it mean by coincident lines between features?

Question 16

An unclosed polygon will result in:

A) both pseudo nodes and dangling nodes
B) dangling nodes
C) pseudo nodes

Question 17

Shapefiles are topology-based.

Question 18

Explain why the 1947 U.S. National Map Accuracy Standard cannot be applied to GIS data.

Question 19

Define "topological errors."

Question 20

The new National Standard for Spatial Data Accuracy (NSSDA) does not stipulate threshold accuracy values that GIS data producers must achieve.

Question 21

Dangling nodes are a common topological error in line layers. Describe one possible cause of dangling nodes.

Question 22

Describe the three basic steps in using a topology rule in ArcGIS.

Question 23

Explain the function of the cluster tolerance.

Question 24

Which of the following has an acceptable dangling node?

A) a two-way street
B) none of these is correct
C) a street intersection
D) a dead-end street

Question 25

The National Standard for Spatial Data Accuracy defines the accuracy in terms of the root mean square (RMS) error. How is the RMS error derived?

Question 26

Give an example of a polygon feature class that can benefit from the topology (polygon) rule of "Must not overlap with."