Expander

Description

This functor expands or contracts previous patches of a certain class or category.

Inputs

Name	Type	Description
Landscape	Categorical Map	Map of classes or categories.
Probabilities	Map	Map of spatial probabilities.
Changes	Change Matrix	Matrix of number of changes.
Transition Parameters	Transition Function Parameter Matrix	Matrix of transition function parameters consisting of Mean Patch size, Patch size variance, and isometry. By varying these parameters, various spatial patterns can be reproduced (see examples on

Optional Inputs

<b>Name:</b> neighborWindowLines<br> <b>Type:</b> PositiveInt<br> <b>Description:</b> Number of lines of the neighbor search window.<p>

<b>Name:</b> neighborWindowColumns<br> <b>Type:</b> PositiveInt<br> <b>Description:</b> Number of columns of the neighbor search window.<p>

<b>Name:</b> pruneFactor<br> <b>Type:</b> Double<br> <b>Description:</b>A multiple of the quantity of cells to be changed. This is used in order to specify the size of the vector where cells are ranked for subsequent draw.

Outputs

Changed Landscape	Categorical Map
Corroded Probabilities	Map

|| Remaining Changes | Change Matrix | Matrix of remaining quantity of changes for each type of transition in case the functor does not succeed in making all specified changes.

| |

Group

Simulation

Notes

DINAMICA uses as a local CA rule and a transition engine composed of two complementary transition functions, the Expander and the Patcher. DINAMICA splits the cell selection mechanism into these processes. The first process is dedicated only to the expansion or contraction of previous patches of a certain class, and it is called Expander. The second process is designed to generate or form new patches through a seeding mechanism, and it is called Patcher. The Patch Isometry is a number varying from 0 to 2. The patches assume a more isometric form as this number increases. The size of new patches and expansion fringes are set according to a lognormal probability distribution. Therefore, it is necessary to specify the parameters of this distribution represented by the mean and variance of the patch sizes to be formed. The combination of DINAMICA's transition function presents numerous possibilities with respect to the generation and evolvement of spatial patterns of change.

<p>In the Expander function, a new Pij spatial transition probability depends on the amount of cells type j around a cell type I, as depicted bellow.

<p align=“center”><img border=“0” src=“images/Expander001.gif” width=“244” height=“401”><br> Transition probabilities after convoluting the expander kernel.

Internal Name

Expander