Rachel Robison
Chapter 6.2 Review Questions
5. What type of raster filter would you use to enhance the high-frequency characteristics in a remotely
sensed image?
To enhance the high frequency characteristics in a remotely sensed image, you would use spatial
convolution filtering. Spatial convolution filtering can be used to enhance low frequency detail,
high frequency detail, and edges in both raster thematic maps and digital images.
6. What filter would you use to emphasize the low-frequency, slowly varying characteristics in a raster
map or image?
To emphasize the low frequency, slow varying characteristics in a raster map or image, you
would use a high frequency filter. High frequency filtering is applied to raster maps or images to
remove the slowly varying components and enhance the high frequency local variations.
7. Describe a typical spatial analysis problem that requires zonal analysis.
An example of a spatial analysis problem that requires zonal analysis would be if a watershed is
overlaid on a LiDAR-derived digital elevation model. The DTM elevation data represents the
input raster value that will used to compute various statistics by zone.
8. Why is texture in an image or map important? What algorithm would you use to extract texture
information from a high-spatial-resolution digital aerial photograph? Why did you select this particular
algorithm?