Terrain Analysis Flashcards

1
Q

Least Cost Path

A

Uses Distant Function Analysis to determine LCP from a destination point to a source. The LCP is the path that will “cost the least” depending on which metrics are used to define cost.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Cost surfaces vs. friction cost surfaces

A

Cost Surfaces-cost distance surface requires a source location dataset and a cost raster as inputs.
Friction cost surfaces-the friction factor (F), to compensate for the bumpiness of the surface, times the distance to travel divided by the miles per gallon the car gets on flat, smooth surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Processing flow for determining a least cost path

A

To create the path, first a cost distance surface must be created, which requires a source location dataset and a cost raster as inputs.

  • The source is the starting point of your proposed feature for analysis.
  • A cost raster identifies the cost of traveling through each cell
  • Calculates the least accumulative cost distance for each cell from or to the least-cost source over a cost surface.
  • Travel direction identifies if the mover is starting at a source and moving to non-source locations, or is starting at non-source locations and moving back to a source.

source, cost raster, cost distance, direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Flow direction (including data storage)

A

Creates a raster of flow direction from each cell to its steepest downslope neighbor.
Data storage-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

flow accumulation

A

Creates a raster of accumulated flow into each cell. A weight factor can optionally be applied

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Stream delineation

A

Assigns a numeric order to segments of a raster representing branches of a linear network
-The results of the Flow Accumulation tool can be used to create a raster stream network by applying a threshold value to select cells with a high accumulated flow.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Watershed delineation

A

Watershed determines the contributing area above a set of cells in a raster.
-The value of each watershed will be taken from the value of the source in the input raster or feature pour point data. When the pour point is a raster dataset, the cell values will be used. When the pour point is a point feature dataset, the values will come from the specified field.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Sinks and Pit-filling

A

Sinks (and peaks) are often errors due to the resolution of the data or rounding of elevations to the nearest integer value.
-Sinks should be FILLED to ensure proper delineation of basins and streams. If the sinks are not filled, a derived drainage network may be discontinuous.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The relationship between surface flow and aspect

A

Surface flow is determined by the steepest (slope) downhill direction (aspect).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Slope Calculations- NEAREST NEIGHBOR METHOD

A

Calculates a nearest neighbor index based on the average distance from each feature to its nearest neighboring feature.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Slope Calculations- 3rd ORDER FINITE DIFFERENCE

A

Similar to nearest neighbor but corners are considered as well. The first four have a higher weight in the calculation. Good for rough terrain.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly