Deck 3: Spatial Data Input and Manipulation

Question 1

Digitising is the process of

A) entering the coordinates of a number of point features into a GIS via keyboard
B) converting paper maps or images to digital vector data
C) capturing vector data using GPS
D) collecting vector data through crowdsourcing

Answer 1

B

Question 2

To digitise a paper map, one first needs to establish control points. The control points may be

A) road intersections
B) points on soil boundaries
C) points on contour lines
D) centre points of water bodies
E) all of the above

Answer 2

A

Question 3

The accuracy of vector data captured through digitising is independent of

A) the number of the points selected to approximate the shape of the features
B) the number of the geographical features selected to digitise from the original map
C) the density of the points selected to approximate the shape of the features
D) the accuracy of the individual points selected to approximate the shape of the features
E) the accuracy of the original map

Answer 3

B

Question 4

Georeferencing an image in GIS involves

A) selecting at least three control points
B) mathematically establishing linear or non-linear relationships between image coordinates and real-world coordinates
C) transforming the image so that each location on the image can be defined in real-world coordinates
D) all of the above

Question 5

Raster data can be captured

A) by means of remote sensing
B) by means of GNSS
C) through on-screen digitising
D) through tablet digitising

Question 6

Which of the following is correct?

A) Direct transfer of spatial data allows the data to be edited.
B) Direct transfer of spatial data is the main means of importing data with complex data formats.
C) Direct transfer of spatial data allows the non-native data to be translated on the fly.
D) Direct transfer of spatial data does not allow the non-native data to be translated on the fly.

Question 7

Vectorisation may

A) increase the thickness of line features
B) change the orientation of features
C) alter the attribute values of features
D) distort the shapes of features

Question 8

Rubber sheeting

A) reproduces a map on a rubber sheet
B) mathematically stretches one map layer along a specific direction
C) mathematically stretches one map layer in all directions in order to enlarge it
D) geometrically adjusts map features to force a data layer to fit a base map

Question 9

An affine transformation requires a minimum of

A) 3 control points
B) 6 control points
C) 9 control points
D) 10 control points

Question 10

Spatial data accuracy refers to

A) how close the spatial data are to a true representation of reality
B) how much detail the spatial data contain about the geographical features
C) how much bias is contained in the spatial data
D) what level of detail at which the spatial data are recorded

Question 11

Spatial data precision refers to

A) how close the spatial data are to a true representation of reality
B) how much detail the spatial data contain about the geographical features
C) how much bias is contained in the spatial data
D) what level of detail at which the spatial data are recorded

Question 12

High accuracy implies high precision and vice versa

Question 13

The positional accuracy of a point feature is associated with

A) errors in its recorded x coordinate
B) errors in its recorded y coordinate
C) errors in its recorded z coordinate
D) all the above

Question 14

The positional accuracy of a line feature is associated with

A) errors in the locations of the individual points selected to represent the feature
B) errors in locating well-defined points along the line feature
C) both a) and b)
D) neither a) nor b)

Question 15

The accuracy of the air temperature data recorded at a number of geographically distributed meteorological stations can be assessed using

A) RMSE
B) cross-tabulation
C) standard deviation
D) mean

Question 16

The accuracy of soil classification on a soil map can be assessed using

A) RMSE
B) cross-tabulation
C) standard deviation
D) mean

Question 17

With the classification error matrix below, what is the overall accuracy of the land use classification?

A) 100%
B) 27.7%
C) 29%
D) 83%

Question 18

Lineage of a spatial dataset does not describe

A) the scale of its source data
B) the date of its source data
C) the data capture and processing methods
D) the layout of its source maps

Question 19

Manual digitising is a significant source of errors in spatial data. But which of the following is not typically an error from manual digitising?

A) undershoot and overshoot
B) spikes
C) displacement
D) incomplete areal coverage
E) knot

Question 20

Vector to raster conversion may cause loss of information because

A) small polygons could be lost
B) a point feature can only be represented using a single grid cell
C) real-world locations of geographical features can no longer be determined
D) measurement becomes inaccurate

Question 21

Slivers are long and narrow polygons generated when

A) overlaying two layers with some common boundaries that were digitised separately
B) producing buffers around area features
C) digitising river banks
D) digitising long and narrow area features

Question 22

The quality of data produced from an overlay procedure is

A) as good as the best data input to the process
B) as good as the worst data input to the process
C) better than the best data input to the process
D) irrelevant to the input data