GIS Spatial Analysis Methods 2 — Questions and Answers
Question 1: Which spatial analysis technique identifies areas within a specified distance of a geographic feature?
- Kriging
- Buffer analysis (Correct answer)
- Thiessen polygon
- Viewshed analysis
Correct answer: Buffer analysis
Buffer analysis creates zones of specified distance around points, lines, or polygons to identify areas of proximity.
Question 2: What does the term 'spatial autocorrelation' measure in GIS analysis?
- The accuracy of GPS coordinates
- The degree to which similar values cluster together in space (Correct answer)
- The overlap between two polygon layers
- The density of point features per unit area
Correct answer: The degree to which similar values cluster together in space
Spatial autocorrelation measures whether nearby locations tend to have similar attribute values, quantified by statistics like Moran's I.
Question 3: In kernel density estimation, what does increasing the bandwidth (search radius) do to the output?
- Creates sharper, more localized peaks
- Produces a smoother, more generalized surface (Correct answer)
- Increases the total volume under the density surface
- Decreases computational processing time
Correct answer: Produces a smoother, more generalized surface
A larger bandwidth spreads influence over a wider area, resulting in a smoother density surface that generalizes local variation.
Question 4: Which interpolation method is considered an exact interpolator, meaning it honors all sample data points?
- Trend surface analysis
- Inverse distance weighting (IDW)
- Spline interpolation (Correct answer)
- Moving average
Correct answer: Spline interpolation
Spline interpolation is an exact interpolator that passes through all control points while maintaining a smooth surface.
Question 5: What is the primary purpose of a cost-distance analysis in GIS?
- Calculating Euclidean distances between features
- Determining the least-cost path across a friction surface (Correct answer)
- Measuring the perimeter of polygons
- Identifying the nearest neighbor for each point
Correct answer: Determining the least-cost path across a friction surface
Cost-distance analysis accumulates travel costs across a raster surface to determine the least-cost path between locations.
Question 6: When performing a spatial join, what happens when a point falls outside all polygon boundaries?
- The point is automatically deleted from the output
- The point retains a null value for the polygon attributes (Correct answer)
- The point is assigned the attributes of the nearest polygon
- The analysis throws an error and stops
Correct answer: The point retains a null value for the polygon attributes
Points outside polygon boundaries receive null (empty) values for the polygon attributes unless a 'nearest' match type is specified.
Question 7: Which statistical test is used to evaluate whether a point pattern is clustered, random, or dispersed?
- Chi-square goodness of fit
- Average nearest neighbor analysis (Correct answer)
- Pearson correlation coefficient
- Standard deviational ellipse
Correct answer: Average nearest neighbor analysis
Average nearest neighbor analysis compares observed mean distances between nearest neighbors to expected distances under complete spatial randomness.
GIS Spatial Analysis Methods 2
Which spatial analysis technique identifies areas within a specified distance of a geographic feature?