Classification of the area by the results of types/states and heterogeneity approaches
The Spectral based organisation is then re-arranged by the textural one through a GIS modelling. Which ends up in a spatial organization potentially composed of a maximum number of 36 classes.


Final Spectral and Textural based organization
Intrinsic Remote Sensing Labelisation of Classes
To give a first stage remote sensing label to the classes, they are analysed following their spectral and disturbance level behaviours.

The spectral behaviours are studied through the knowledge brought by the Tasseled Cap (Crist and Cicone, 1984) model applied to the facts furnished by the actual data resulting from the classification process.

The disturbance is studied by building knowledges concerning their relative levels, very low to very high, through statistical analysis.

The results are presented in the table below.

Water Vegetation Urdan
	Spectral Texture	1	2	3	4	5	6
Homogeneous not disturbed	1	11	21	31	41	51	61
	2	12	22	32	42	52	62
	3	13	23	33	43	53	63
	4	14	24	34	44	54	64
Heterogeneous very disturbed	5	15	25	35	45	55	65
	6	16	26	36	46	56

Table 1 : Remote sensing Class Labels.
Reading of the types: 66 is class 6 of the spectral based organization at the level 6 of the “disturbance organization”.

The last step of labelisation, is done through a survey and questionnaire, whose sampling frame is dictated spatially and statistically by the modeled reality obtained from the previous remote sensing approach. This last step is aiming at the providing of common understandings and meanings to the classes, plus very precise answers to very clearly defined questions.

Conclusion
Current results obtained in the study of the Dengue show that it is now possible to identify and localize precisely environmental indicators and factors of viral diseases. Furthermore it is also now possible to predict estimates of where the viral diseases could probably and spatially burst, and at what level of incidences. Next developments would concern the introduction of dynamics and time, and enlargement of the study of factors and indicators to social, economical, cultural and ecological parameters.

References

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