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Calculate Corridor Housing Density

Calculate Target Housing Density is designed for estimating an appropriate housing density that will meet specific wildlife conservation targets. The user specifies the minimum area requirement for core habitat and a disturbance distance.

The tool uses iterative Monte Carlo simulations of random patterns to simulate the influence of houses and roads on the size of habitat cores. After each simulation run, the mean percent area of "core habitat" is compared with the user specified target. The number of houses is adjusted for each subsequent simulation until a solution is reached. Processing stops when a solution within 5% of the target is reached.

When the final solution is reached, a message box displays the density of houses (in acres) that satisfied the target parameters. Outputs include a summary table of all simulation runs, and example shapefiles of cores and houses representing the final simulation that satisfied target parameters.


Illustration

Figure 1. Example of output from Calculate Corridor Housing Density
Figure 1. Example output. A random pattern of structures at a density that produces an average distance between structures equal to the target value provides high probababilty that the landscape matrix is permeable for the target species. One of many possible movement routes is indicated by the dashed arrow.

Usage Tips

HINT: Using dissolve to convert a multipart analysis extent layer to a single part layer can dramatically improve processing speed.


Command line syntax

CalcTargetDensity2 <Output_Table> {Number_of_Iterations} <Analysis_Extent> {Constraint_Layer} <Minimum_Corridor_Width> <Disturbance_Distance> {Acres | Hectares | Square Kilometers | Square Meters | Square Miles}

Parameters
Expression Explanation
<Output_Table>

The name of a table where summary data will be stored.
{Number_of_Iterations}

The number of iterations to run each Monte Carlo simulation. Note: Execution time is multiplied by the number of iterations selected.
<Analysis_Extent>

Polygon layer to be used as boundary for analysis extent. This layer must have a projection with units in meters.
{Constraint_Layer}

Polygon layer used to confine the random placement of houses. This layer must be in same projection as, and overlap with, the Analysis Extent. Specifying a Constraint Layer is useful for masking out areas that cannot be developed. If no Constraint Layer is specified, houses will be placed randomly throughout polygons contained in the Analysis Extent.
<Minimum_Corridor_Width>

The mimimum width of undisturbed habitat the target species requires for movement security.
<Disturbance_Distance>

The distance from roads and houses the target species is likely to avoid or where habitat quality is degraded. This value must be specified in square meters.
{Acres | Hectares | Square Kilometers | Square Meters | Square Miles}

Select the units for reporting output densities.
Command Line Example







 Scripting syntax




CalcTargetDensity2 (Output_Table, Number_of_Iterations, Analysis_Extent, Constraint_Layer, Minimum_Corridor_Width, Disturbance_Distance, Output_Units) 

Parameters




Expression
Explanation




Output Table (Required) 


The name of a table where summary data will be stored.






Number of Iterations (Optional) 


The number of iterations to run each Monte Carlo simulation.  Note: Execution time is multiplied by the number of iterations selected.






Analysis Extent (Required) 


Polygon layer to be used as boundary for analysis extent.  This layer must have a projection with units in meters.






Constraint Layer (Optional) 


Polygon layer used to confine the random placement of houses.  This layer must be in same projection  as, and overlap with, the  Analysis Extent.  Specifying a Constraint Layer is useful for masking out areas that cannot be developed.  If no Constraint Layer is specified, houses will be placed randomly throughout polygons contained in the Analysis Extent.






Minimum Corridor Width (Required) 


The mimimum width of undisturbed habitat the target species requires for movement security.






Disturbance Distance (Required) 


The distance from roads and houses the target species is likely to avoid or where habitat quality is degraded.  This value must be specified in square meters.






Output Units (Optional) 


Select the units for reporting output densities.






Script Example