Optimising Scale
My Cognition of Scale is as an endemic feature of spatial data that was previously viewed as a problem but is more properly regarded as an opportunity for new ways of visual spatial analysis and modelling
BUT
Context
PPT Slide
HOWEVER..
Most previous work is not wrong just a little flawed!
Zoning Systems are a key part of GIS and SCALE is a key unknown in zone design
but
Zone Design is much neglected and few zone engineering tools exist
Its a HARD problem because it involves the manipulation of both SCALE and AGGREGATION components
and there is little useful theory to guide the process
Spatial Patterns are SCALE sensitive!
How is scale handled at present?
Badly is the short answer
Scale is not undercontrol!
Scale AND Aggregation are inseparably interlinked
Some Definitions
Some Observations
Spatial Analysis and Modelling assumes you know the scale at which patterns or relationships exist
There are very few spatial analysis tools which are multi scaled and multi-aggregational
Important to start to DESIGN zones to MANAGE the scale and aggregation components directly!
Example using 1991 census data for Leeds - Bradford region
Unemployment Equal Population
Unemployment Positively correlated with Ethnic Minorities
Unemployment negatively correlated with unemployment
The 1991 Deprivation Index Signed Chi-squared function
Leeds Wards
Leeds - New Zoning
A new approach!
Zone Design can also be used as a Spatial Analysis and Modelling tool
How do you DESIGN ZONES?
Handling the AGGREGATION component
ZDES v4
HARD!
ZDES Algorithms
Choice of F(Z)
Constrained ZDES
These design functions are best handled as inequality constraints so the zone design problem is analogous to mathematical programming formulation
ZDES either constrained or unconstrained assumes you know the value of M
Build a ZDES with SCALE and AGGREGATION
BUT..
Scale Zooming
ZDES code is very fast so the run times needed to run it N-1 times is not a practical problem as compute times diminish with increasing M
Multiple ZDES runs
BUT what do you do with all the output?
Other Problems
Map Animation
MPEG Movies from Maps
Java to the rescue!
Map animation
Multiscale Spatial Analysis
An example of looking for optimal scale patterns in spatial analysis of long term limiting illness data in Northern England
Ward Level map of LLTI
GAM/K cluster identification
The hope is that some patterns or relationships or models will show chaotic behaviour as scale is changed
Affective Spatial Analysis?
Conclusions
Email: stan@geog.leeds.ac.uk
Home Page: http://www.geog.leeds.ac.uk/staff/s.openshaw/