Surface Analysis

Question 1

Slope

Answer 1

Identifies the slope (gradient, or rate of maximum change in z-value) from each cell of a raster surface.
-rate of maximum change in z-value from each cell.

Question 2

Aspect

Answer 2

Identifies the downslope direction of the maximum rate of change in value from each cell to its neighbors.

Question 3

Environment settings in ArcMap

Answer 3

Useful Environment Settings

• Current and scratch workspace
• Output coordinate system
• processing extent
• Cell Size
• Analysis Mask

Question 4

DEM

Answer 4

DEM- Digital Elevation Models- most common digital data of the shape of the earth’s surface.

• used as input to quantify characteristics of land surface
• accuracy is determined primarily by the resolution.

Question 5

Slope measurement and conversion

Answer 5

-range of values in output depend on type of measurement unit.
-for degrees, range of slope is 0-90. for percent rise, range is 0 to essentially infinity.
Rise/run *100= percent.
To get from point A to point be, you ‘rise’ up X and ‘run’ over Y.

Question 6

Aspect calculation

Answer 6

Aspect is expressed in positive degrees from 0-359.9, measured clockwise from north.
Represented with a color wheel delineating direction in 45 degree increments.

Question 7

Environment Setting- CELL SIZE

Answer 7

Default is the maximum cell size of the inputs.

Question 8

Topographic (elevation) profile

Answer 8

A topographic profile is a cross-sectional view along a line drawn through a portion of a topographic map. In other words, if you could slice through a portion of the earth, pull away one half, and look at it from the side, the surface would be a topographic profile.