Deck 11: Vector Data Analysis

Question 1

Intersect is an overlay method as well as a spatial join option. Will you get the same result from both operations?

Answer 1

No, you will not get the same result from both operations. While both Intersect as an overlay method and a spatial join option involve combining two datasets based on their spatial relationship, they function differently and thus produce different results.

The Intersect overlay method creates a new dataset that includes only the areas where the input datasets overlap. It essentially finds the common area shared by the datasets.

On the other hand, a spatial join merges the attributes of two datasets based on their spatial relationship, not just where they overlap. It assigns the attributes of one layer to another based on location or proximity.

Therefore, while both operations involve spatial relationships, they serve different purposes and yield different results.

Question 2

Which of the following analyses is also called multi-distance spatial clustering analysis?

A) G-Statistic
B) nearest neighbor analysis
C) Ripley's K-Function
D) Moran's I

Answer 2

Ripley's K-Function

Question 3

Suppose an input layer shows a county and an overlay layer shows a national forest. Part of the county overlaps the national forest. We can express the output of an Intersect operation as [county] AND [national forest]. How can we express the outputs of a Union operation and an Identity operation (with the county as the input layer) using the Boolean Connector?

Answer 3

No Answer

Question 4

You must use a polygon layer to define the area for clipping in a Clip operation.

Question 5

You are asked to prepare a preliminary map that shows land parcels in a county that meet the following two criteria: (1) within 300 meters of streams, and (2) located in a conservation priority area. You are given two digital maps for the study area: one showing streams and the other showing the priority areas. Describe the procedure that you will use to complete the task.

Question 6

Provide an application example in which a buffer zone is used as an exclusion zone.

Question 7

Which of the following conditions is required by Union?

A) The input layer can be a line or polygon layer but the overlay layer must be a polygon layer.
B) None of these are correct.
C) The input layer must be a polygon layer but the overlay layer can be a line or polygon layer.
D) Both the input and overlay layers must be polygon layers.

Question 8

Which overlay method uses the Boolean operation of XOR?

A) Symmetrical difference
B) Union
C) Identity
D) Intersect

Question 9

The concept behind buffering is similar to proximity in spatial data query. Provide an example in which you must use buffering instead of spatial data query.

Question 10

Which of the following statements is true about vector data analysis?

A) The accuracy of vector data analysis depends on the accuracy of inputs in terms of their location and shape.
B) Vector data analysis uses points, lines, and polygons as inputs and The accuracy of vector data analysis depends on the accuracy of inputs in terms of their location and shape.
C) Vector data analysis may apply to all, or selected, features in an input layer.
D) All of these are correct
E) Vector data analysis uses points, lines, and polygons as inputs.

Question 11

If you use a line layer and a polygon layer in an overlay operation, the output will be:

A) a line layer and a polygon layer together
B) a line layer
C) a polygon layer

Question 12

Which of the following is true about buffering?

A) You have the options of creating a single ring or multiple rings.
B) You can either dissolve the buffer zones or keep the buffer zones separate.
C) You can buffer with different buffer distances.
D) You can either dissolve the buffer zones or keep the buffer zones seperate and you can have the options of creating a single ring or multiple rings.
E) All of these are correct.

Question 13

ArcGIS does not automatically update the area and perimeter values of an overlay output if shapefiles are used as the input layers.

Question 14

Which operation can remove boundaries between polygons that have the same value of a select attribute?

A) Dissolve
B) Merge
C) Clip

Question 15

Error propagation in overlay operations can be caused by:

A) inaccuracies of attribute data
B) both of these are correct
C) digitizing errors

Question 16

What is the minimum mapping unit?

Question 17

Buffering a point creates a buffer zone that is a ____:

A) square
B) point
C) circle
D) line

Question 18

You have a land use map that shows land use classes of urban, agricultural, commercial, and so on. Which operation will you use to get a new map that only shows agricultural land use?

A) Eliminate
B) Clip
C) Select
D) Erase

Question 19

Both Moran'I and the G-statistic have the global (general) and local versions. How do these two versions differ in terms of pattern analysis?

Question 20

Explain the point-in-polygon operation.

Question 21

Explain the polygon-on-polygon operation.

Question 22

Define "slivers" from an overlay operation.

Question 23

Which overlay method preserves only those features that fall within the area extent common to the input and overlay layers?

A) Identity
B) Intersect
C) Symmetrical difference
D) Union

Question 24

Which overlay method uses the Boolean operation of AND?

A) Identity
B) Union
C) Intersect
D) Symmetrical difference

Question 25

You have downloaded a shapefile from a website that shows toxic waste sites in your state. Which operation will you use to get a map showing toxic waste sites within a 10-mile buffer zone map that you have made around your home?

A) Clip
B) Dissolve
C) Eliminate
D) Erase

Question 26

Both Erase and Eliminate can remove map features from a layer. Explain how the two commands differ in usage.

Question 27

The following figure shows an overlay (Intersect) operation. "A" represents the input (polygon) layer with ID values from 1 to 4; "B" represents the intersect (polygon) layer with the ID values of 10 and 11; and "C" is a graphic representation of the overlay operation.
1) How many polygons will the output have?
2) How many records in the output will have the ID value of 3 from the input layer?
3) How many records in the output will have the ID value of 11 from the intersect layer?

Question 28

A line-in-polygon operation produces a line layer, which typically has more records (features) than the input line layer. Why?

Question 29

Which overlay method combines the area extents from both input layers?

A) Union
B) Identity
C) Intersect
D) Symmetrical difference

Question 30

How does Ripley's K-Function differ from nearest neighbor analysis?

Question 31

Provide an application example in which a buffer zone is used as an inclusion zone.

Question 32

Describe an example in which areal interpolation can be used as a problem-solving tool.

Question 33

Describe a scenario, in which Intersect is preferred over Union for an overlay operation.