Corridor and Cost Allocation Tools
Corridor
How to use Corridor Tool in Arc Toolbox??
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| Corridor Tool |
Path to access the tool
:
Corridor Tool, Distance Toolset, Spatial
Analyst Tools Toolbox
Corridor
Calculates the sum of
accumulative costs for two input accumulative cost rasters.
1. Input cost distance raster
The first input distance
raster.
It should be an
accumulated cost distance output from a distance tool such as Cost Distance or
Path Distance.
2. Input cost distance raster
The second input
distance raster.
It should be an
accumulated cost distance output from a distance tool such as Cost Distance or
Path Distance.
3. Output raster
The output corridor
raster.
The output raster is of
floating-point type.
Cost Allocation
How to use Cost Allocation Tool in Arc Toolbox??
 |
| Cost Allocation |
Path to access the tool
:
Cost
Allocation Tool, Distance Toolset,
Spatial Analyst Tools Toolbox
Cost Allocation
Calculates, for each
cell, its least-cost source based on the least accumulative cost over a cost
surface.
1. Input raster or feature source data
The input source
locations.
This is a raster or
feature dataset that identifies the cells or locations from or to which the
least accumulated cost distance for every output cell location is calculated.
For rasters, the input
type can be integer or floating point.
If the input source
raster is floating point, the Input value raster parameter must be set, and it
must be integer. The value raster will take precedence over the Source field
parameter setting.
2. Source field (optional)
The field used to assign
values to the source locations. It must be of integer type.
If the Input value
raster parameter has been set, the values in that input will have precedence
over the Source field parameter setting.
3. Input cost raster
A raster defining the impedance
or cost to move planimetrically through each cell.
The value at each cell
location represents the cost-per-unit distance for moving through the cell.
Each cell location value is multiplied by the cell resolution while also
compensating for diagonal movement to obtain the total cost of passing through
the cell.
The values of the cost
raster can be integer or floating point, but they cannot be negative or zero
(you cannot have a negative or zero cost).
4. Output allocation raster
The output cost
allocation raster.
This raster identifies
the zone of each source location (cell or feature) that could be reached with
the least accumulative cost.
The output raster is of
integer type.
5. Maximum distance (optional)
The threshold that the
accumulative cost values cannot exceed.
If an accumulative cost
distance value exceeds this value, the output value for the cell location will
be NoData. The maximum distance is the extent for which the accumulative cost distances
are calculated.
The default distance is
to the edge of the output raster.
6. Input value raster (optional)
The input integer raster
that identifies the zone values that will be used for each input source
location.
For each source location
(cell or feature), the Input value raster value will be assigned to all cells
allocated to the source location for the computation. The value raster will
take precedence over the Source field parameter setting.
7. Output distance raster (optional)
The output cost distance
raster.
The cost distance raster
identifies, for each cell, the least accumulative cost distance over a cost
surface to the identified source locations.
A source can be a cell,
a set of cells, or one or more feature locations.
The output raster is of
floating-point type.
8. Output backlink raster (optional)
The output cost backlink
raster.
The backlink raster
contains values 0 through 8, which define the direction or identify the next
neighboring cell (the succeeding cell) along the least accumulative cost path
from a cell to reach its least-cost source.
If the path is to pass
into the right neighbor, the cell will be assigned the value 1, 2 for the lower
right diagonal cell, and continue clockwise. The value 0 is reserved for source
cells.
9. Multiplier to apply to costs (optional)
The multiplier to apply
to the cost values.
This allows for control
of the mode of travel or the magnitude at a source. The greater the multiplier,
the greater the cost to move through each cell.
The values must be
greater than zero. The default is 1.
10. Start cost (optional)
The starting cost from
which to begin the cost calculations.
Allows for the
specification of the fixed cost associated with a source.
Instead of starting
at a cost of zero, the cost algorithm will begin with the value set by Start
cost.
The values must be zero
or greater. The default is 0.
11. Accumulative cost resistance rate (optional)
This parameter simulates
the increase in the effort to overcome costs as the accumulative cost
increases. It is used to model fatigue of the traveler. The growing
accumulative cost to reach a cell is multiplied by the resistance rate and
added to the cost to move into the subsequent cell.
It is a modified version
of a compound interest rate formula that is used to calculate the apparent cost
of moving through a cell. As the value of the resistance rate increases, it
increases the cost of the cells that are visited later. The greater the
resistance rate, the more additional cost is added to reach the next cell, which
is compounded for each subsequent movement. Since the resistance rate is
similar to a compound rate and generally the accumulative cost values are very
large, small resistance rates are suggested, such as 0.02, 0.005, or even
smaller, depending on the accumulative cost values.
The values must be zero
or greater. The default is 0.
12. Capacity (optional)
The cost capacity for
the traveler for a source.
The cost calculations
continue for each source until the specified capacity is reached.
The values must be
greater than zero. The default capacity is to the edge of the output raster.
13. Travel direction (optional)
Specifies the direction of the traveler when applying the source resistance rate and the source starting cost.
- FROM_SOURCE—The source resistance rate and source starting cost will be applied beginning at the input source, and travel out to the non-source cells. This is the default.
- TO_SOURCE—The source resistance rate and source starting cost will be applied beginning at each non-source cell, and travel back to the input source.
If you select the String
option, you can choose between from and to options, which will be applied to
all sources.
If you select the Field option, you can select the field from the source data that determines the direction to use for each source. The field must contain the text string FROM_SOURCE or TO_SOURCE.
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