Automating the administration boundary design process using Hierarchical Spatial Reasoning theory and GIS Francisco Escobar Serryn Eagleson Ian Williamson

Outline –Background –The problem uncovered –Hierarchical Spatial Reasoning (HSR) –Methods to solve the problem –HSR - Applied to Administrative Boundaries –Conclusion

The Problem Throughout history boundaries have been used to divide the space around us into administrative units In the majority of cases these boundaries have been established to facilitate administrative, political and economic purposes

Collector District North West Melbourne Health Division N 3036 Km Postcode

East Gippsland

The problem

Research Objective To identify the principles of Hierarchical Spatial Reasoning and apply them to Administrative polygons design using GIS

Possible solutions Aggregation- current Interpolation- current Reorganisation- proposed

Point Aggregation

Interpolation Process Data Interpolation Formula V t =  U s (a st /  a st ) Errors

Interpolation Errors

Proposed Solution

Hierarchical Spatial Reasoning Hierarchies have been used to break down a number of complex problems Quadtrees, Route Planning Properties Janus Effect Whole Part Near decomposability

Hierarchical Model agency 1 agency 2 Cadastre Mesh Block agency 3

Implementing HSR theory Method to transform the ‘flat’ structure into an equivalent hierarchical structure Rules to reason on the structure Performance analysis in comparison to the non- hierarchical structure. (Timpf and Frank 1997)

Expected Advantages  Enhanced Data Integration  Modifiable Area Unit  Boundary flexibility  Analysis over time

Selected Agencies Australian Bureau of Statistics (ABS) Census Collection District (CCD) Australia Post (AP) Postcode

Boundary Constraints Confidentiality Topography Contiguity Shape

Model Development Aggregation based on attributes If (constraints are met) then add the Polygon to selection else Do Not end Union.Selected

Algorithm Development Data Input Is freq < constraint Select Adjacent Polygons Select Initial Polygon Is counter = total Sort by shape Warning Increment counter Calculate circularity Is circularity < 0.5 Quality Report

Future Models Interactive Boundary Design Thematic and Spatial Aggregation Christaller’s space to boundaries Existing Boundary Infrastructure

Thiessen Polygons - (Martin, 1991 & Openshaw, 1992) Spatial selection approach

Conclusion It is possible to align administrative boundaries according to HSR theory The implemented algorithm offers a solution to the problem of boundary delineation and provides the means for accurate data exchange

Further Research Rural environments Shape HSR properties for boundaries