Diferenças

Aqui você vê as diferenças entre duas revisões dessa página.

--- geopro:raian:bibliografia:vecgca_model [2010/01/22 18:12] – raian
+++ geopro:raian:bibliografia:vecgca_model [2010/02/20 03:51] (atual) – raian
@@ Linha 19: / Linha 19: @@
       * White and Engelen (2000) and O'Sullivan (2001b) proposed an extention of the neighborhoods difinition to the set of all cells that influence the state of a particular cell, adjacent or not, referred to as a raduis of influence and a graph of influence.
     - Most GIS integrated CA models have been used a discrete space representation and a regular tesselation of cells of the same size, and shape similar to the GIS raster model, but these raster-based CA models are sensitive to spatial scale. Several studies have demostrated that the choice of a particular cell size and neighborhood configuration impacts on results of the models developed using these CA models.
+    - Some models use solutions as vector-based or object-based models where the space is defined as a collection of irregular polygons that correspond to real entities in the study area, to mitigate scale sensitivity.
+    - Some implementations of irregular space in CA models:
+      * Using Voronoi polygons -> not necessarily correspond to real-world entities, because a Voronoi polygon represents a region grouping together the set of points closest to a spatial object, but it does not represent the spatial object itself.
+      * Using GIS vector format to define space (Vector cellular automata model) -> a geographic object is the conceptual representation of a real entity such as a city, a farm, and others. Each geographic object has a spatial representation under the cartesian coordinate system, and neighborhood relationships are defined using Voronoi diagrams. Two disadvantages:
+        - The lack of an explicit definition of the neighborhood relationships, because the Voronoi diagram is automatically generated from the vector map that represents the space.
+        - The model does not allow a change of shape or size of the objects, but only change of state.
+      * Defining the space as a collection of irregular cadastral land parcels, with the neighbors composed of all adjacent parcels, parcels accessible from a road, and parcels within a buffer zone. The appearance of a new parcel is based on a set of predefined parcels that changes from one state to another. This model does not allow changes of shape or size of the land parcels.
+    - Changes of size and shape occurs continuously in the real-world, and should to be taken into account, so this inability have to be considered.
+    - **Objectives:**
+      * To present a new vector-based CA model that overcomes the problem of cell-size sensitive by allowing an irregular space tesselation where the neighborhood definition and the transition rules are connected to the real properties of each geographic object within the study area, and that allows geometric transformations of the geometric objects as a result of the transition functions.
+      * To test the vector-based geographic cellular automata (VecGCA) model with real data and compare the results with those obtained using a classical raster-based CA model under the same conditions.\\
+    - **The proposed VecGCA model:**
+      * **Conceptual Model** -> Three components that correspond to modification to the classical CA model:
+        - //Space Definition// -> Space is composed of a collection of georeferenced geographic objects of irregular shape that represents the real-world entities. Each poligon is in a specific state and can define its propper transition function and neighborhood. Each geographic object is connected to others through adjacent sides and together they compose the whole space of a study area.
+        - //Neighborhood Definition// -> The neighborhood defines which objects determine the change of shape of a central geographic object. Usually, in geographic applications, a geographic entity is influenced by adjacent or nonadjacent entities separated by a distance //d//. In VecGCA model, the neighborhood is defined as an external buffer (region of influence) around each geographic object, and all the objects (adjacent or not) that are partially or totally within the region of influence defined by //d// are the neighbors of the central object. The size of the buffer that delineates the region of influence is expressed in lenght units and is selected by the user.
+          * {{geopro:raian:bibliografia:neighborhood_vecgca.jpg?300}}
 ^^[[geopro:raian:bibliografia|Voltar]]^^\\