1. HIMMELI - Heuristic three-level Instrument combining urban Morphology, Mobility, service Environments and Locational Information
Morphologically structured agent based simulation model of urban retail system
Sanna Iltanen
Tampere University of Technology, Finland
COST TU1002 WG Meeting Edinburgh

2. EVOLUTION OF RETAIL SERVICES
MODEL PRINCIPLE
The holistic model of the urban retail system which utilises the accessibility measures in multiple ways
The model combines approaches of urban morphology, spatial interaction modeling and agent based modeling techniques
Model structure:
INPUT
OUTPUT
MODEL
retail services
EVOLUTION OF RETAIL SERVICES
households
transportation system

3. theoretical framework
Network city theory
Model framework Dupuy ’s triple layered network
Households
Retail Units / Types
(Daily/Specilaty)
Road Network

4. theoretical framework
Gabriel Dupuy’s three level network theory defines the overall framework for the model
The urban morphological methodologies is exploited to define the retail unit typologies and in handling the infrastructural networks
The interaction principles in the model are derived from the tradition of spatial interaction modeling
Agent based modeling enables the observation of spatial self-organization of retail units based on local interactions
The bottom up approach allows also the observation of emergent phenomena and relates the model to the complex system theory

5. Model flowchart Initialisation Phase Simulation Phase Input data
Get network data & calculate travel cost matrix
Get retail unit typology & locations
Get household typology & locations
Calculate Accessibilities
Simulation Phase
Calculate utilities for households
simulation cycles
Update retail unit accounts
Remove unprofitable retail units
Create new retail units

6. ACCESSIBILITY IN THE MODEL
Simulation Phase
ACCESSIBILITY FUNCTIONS
TRAVEL COST
MATRIX
Acc R-R
accessibility from retail unit to all other retail units
2. Production & consumption level
Acc Hh-R
accessibility from household location to retail unit affects to utility
1. Agent level
Acc network
Accessibility as a network property affects on locations of new retail units
3. Infrastructural level

7. INDICATORS At current stage the focus is on roadnetwork
mean depth of road centre line network (or integration)
travel cost in terms of distance (meters)
travel cost in terms of time (minutes)
The travelcost matrix (of discrete space) enables combination of several accessibility levels (e.g. road network based, public transportation based, walkability based).

8. input
census data of households (grid format database, three income brackets)
register database of companies (classification based onNACE Rev.2)
road network database or general travel cost matrix

9. output dynamics: the spatial self-organization of retail system
temporal behavior of the system: stable / periodic / chaotic / complex
Scenario 1
Scenario 2
Scenario N …

10. USEFULNESS IN PRACTICE
The model increases understanding of the feedback loops and cumulative influence of boundary conditions related to infrastructure, mobility and service typologies
The model allows observation of possible development paths of the system as one of the attributes is changed
Possible phase transitions in spatial distribution of (retail) services can be anticipated

11. THANK YOU!