Raster: Focal, Zonal, and Global Operations

Question 1

Functions: explain focal

Answer 1

output raster includes input value of a cell and the neighboring cells around it

Question 2

Define low pass filter

Answer 2

filter that equally weights all filter cells and reduces local detail

Question 3

Define high pass filter

Answer 3

filter that exaggerates local detail and can be used to locate max rates of change such as edges

Question 4

What are the three edge extension techniques?

Answer 4

1. wrap around
2. replication
3. constant padding

Question 5

Define focal variety statistic

Answer 5

used to determine areas with more than one land cover

Question 6

Functions: explain zonal

Answer 6

produces an output raster dataset with the value of the cell at the location plus its associates cartographic zone (adjacent or disconnected)

Question 7

Define zone

Answer 7

All cells with the same value

Question 8

Zonal: majority vs maximum

Answer 8

majority: the most frequently occurring value in each zone is assigned to all cells in that zone

maximum: the highest value in each zone is assigned to all the cells in that zone

Question 9

Zonal: variety vs range

Answer 9

variety: the number of unique values in each zone is assigned to all cells in that zone

range: the difference between the max and the min values in each zone is assigned to all cells in that zone

Question 10

Functions: explain global

Answer 10

produces an output raster where each cell location is a function of the cells combines from the various input raster datasets

Ex: euclidean distance