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From | "P. Wilner Jeanty" <pwjeanty@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | st: Updates for nearstat and splagvar available for download |
Date | Mon, 26 Dec 2011 12:01:49 -0600 |
Hi All, Thanks to Kit Baum, new versions for -nearstat- and -splagvar- are available on SSC. Using Mata, the Stata’s new matrix language, -nearstat- calculates distances, generates distance-based variables, and exports the distances to a Stata matrix, a Mata file, or a text file. To generate the variables, nearstat performs, for each observation in a georeferenced Stata dataset, a series of computational tasks including, but not limited to, calculating distance-weighted descriptive statistics over all neighbors, nearest neighbors, and neighbors falling in a specified distance band; calculating distance to nearest neighbors; counting the number of neighbors falling in a specified distance band; and determining whether a specified (e.g., first, second, third,…) nearest neighbor falls within a certain distance band. Central to the power behind -nearstat- is a striking Mata function, -minindex()-. Updates include some fixes (e.g., display format when option des() is specified), an option to request a variable holding the minimum or maximum distance from each observation to its neighbors, and an option -iidist()- to request a variable holding one-to-one distance (i.e., diagonal elements) when latitudes and longitudes specified in -varlist1- are different from those specified with the -near()- option. -splagvar- generates spatially lagged variables of order up to 3, constructs the Moran scatter plot, and calculates global Moran's I statistics to test for the presence of spatial dependence in a variable. Spatially lagged variables can now be generated for a specific equation when the equation(#) option is specified. If equation(#) option is specified, then -splagvar- form the names of the spatially lagged variables by prefixing the names of the variables whose spatial lags were taken with wy#_, wx#_, w2x#_, and w3x#_, where # stands for the equation number. Otherwise, names are formed by prefixing the supplied variable names with wy_, wx_, w2x_, and w3x_. To install the new versions type the following command lines and then restart Stata. ssc install nearestat, replace ssc install splagvar, replace Best wishes, Wilner ---------------------------- P. Wilner Jeanty Rice University MS 208 6100 Main Street Houston, TX 77005 Phone: (713) 348-3114 Email: pwjeanty@rice.edu Web: http://www.kinder.rice.edu http://www.stasacode.com http://ideas.repec.org/e/pje95.html * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/