This document describes a spatio-morphological model for predicting the spread of built-up areas in a coastal region of France. The model uses image processing and mathematical morphology operations like dilation and erosion to simulate the past and future expansion of development. The model was validated by comparing simulated and actual growth from 1977 to 1990. Test results showed the model could accurately predict the approximate shape and location of new development to within 1-3 pixels. The improved model was then used to simulate potential growth trajectories out to 2010 under different growth rate scenarios.

1. A Spatio-morphological Modelling for Spread Predicting Christine Voiron – Canicio UMR ESPACE - University of Nice Sophia Antipolis / CNRS

5. Stage 1: determining the spatial rules

11. Y Coefficient simil Image A1: Built-up areas in 1977 Image B: closing of size i I = i+ 1 simil is higher ? Elimination of points falling into sea, ponds, protected zones Image A2: observed built-up areas in 1990 Image B: result of closing simil (A2,B) = surface of intersection (A2,B) / surface of union (A2,B) Y Matching Flow chart of the spread modelling by image processing N The ctiterion for stopping the spread is the value of simil. The matching is performed for all probable sizes of closing, one takes that which maximizes simil

13. Application: basic model simil calculated on the new built-up areas = 0.257 Results of the model 71% 65% 58% 48.5% Margin of error 3 pixels Margin of error 2 pixels Margin of error 1 pixel Pixel agreement

14. Improving the model Subset 1: « attractive zones »: Stage 1: new spread process Subset 2: rest of the built-up areas Stage 2: protocol used to the 1st model

15. Application: Improved model simil calculated on the new built-up areas = 0.41 Results of the model 77% 72% 65% 58% Improved model 71% 65% 58% 48.5% Basic model Margin of error 3 pixels Margin of error 2 pixels Margin of error 1 pixel Pixel agreement

16. Stage 4: simulating the future extension of built-up areas This improved model is applied to seek the broad outlines of the future built-up surfaces, up to 2010 2 spread rates have been tested 6 % 3 %

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