Local and Global Spatial Statistics

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er Science, vol. 960, pp. 426–446, Springer-Verlag, Heidelberg (1995) Haesevoets, S.: Modelling and Querying Spatio-temporal Data. PhD thesis, Limburgs Universitair Centrum (2005) Kanellakis, P.C., Kuper, G., Revesz, P.Z.: Constraint query languages. J. Comp. Syst. Sci. 51, 26–52 (1995) Kuper, G.M., Libkin, L., Paredaens, J. (eds.) Constraint Databases. Springer-Verlag, Heidelberg (2000) Paredaens, J., Van den Bussche, J., Van Gucht, D.: First-order queries on finite structures over the reals. SIAM J. Comp. 27(6), 1747–1763 (1998) Paredaens, J., Van den Bussche, J., Van Gucht, D.: Towards a theory of spatial database queries. In: Proceedings of the 13th ACM Symposium on Principles of Database Systems, pp. 279–288 (1994) Revesz, R.Z.: Introduction to Constraint Databases. SpringerVerlag, Heidelberg (2002) Rigaux, Ph., Scholl, M., Voisard, A.: Introduction to Spatial Databases: Applications to GIS. Morgan Kaufmann, (2000) Tarski, A.: A Decision Method for Elementary Algebra and Geometry. University of California Press, Berkeley (1948) Vandeurzen, L.: Logic-Based Query Languages for the Linear Constraint Database Model. PhD thesis, Limburgs Universitair Centrum (1999)

Linearization  Indexing of Moving Objects, Bx -Tree  Space-Filling Curves

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Main Text Moran’s I and Geary’s C are global indices of spatial association that include all the locations in the data. A spatial contiguity matrix W ij , with a zero diagonal, and the offdiagonal non-zero elements indicating contiguity of locations i and j are used to code proximities. The most commonly used global indicators of spatial autocorrelation are Moran’s I and Geary’s C which are defined as:   N i j Wij Zi Zj I=  (1)  2, i i Wij i Zi   (N − 1) i j Wij (xi − xj )2 C= . (2)    2( i j Wij ) i Zi2 Z i is the deviation of the variable of interest xi from the mean x¯ at location i, and N is the number of data points. Getis and Ord (1995) have defined several local measures including G* which is defined as follows:  j Wij (d)xj ∗  Gi ∗ = . (3) j xj Anselin (1995) defines a local version of the Moran’s I as well as LISA statistics. These local measures have been used to identify spatial “hot-spots.” The local Moran I i is defined as:  Ii = Zi Wij Z j . (4) j

Link-Node Model  Road Network Data Model

LISA Statistics  Local and Global Spatial Statistics

Local autocorrelation statistics make it possible to assess the spatial association of a variable within a particular distance of each observation. Cross References  Spatial Contiguity Matrices

Recommended Reading

Local and Global Spatial Statistics S UMEETA S RINIVASAN School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA

Anselin, L.: Local indicators of spatial association – LISA. Geogr. Anal. 27, 93–115 (1995) Ord, J.K., Getis, A.: Local Spatial Autocorrelation Statistics: Distributional Issues and an Application. Geogr. Anal. 27, 286–306 (1995) Cliff, A., Ord, J.K.: Spatial Autocorrelation. Pion, London (1973)

Synonyms Getis-Ord ind