The gstat Package - NexTag Supports Open Source Initiatives

8 get.contrSee Alsoncp.gridExamplesdata(fulmar)summary(fulmar)get.contrCalculate contrasts from multivariable predictionsDescriptionUsageGiven multivariable predictions and prediction (co)variances, calculate contrasts and their (co)varianceArgumentsget.contr(data, gstat.object, X, ids = names(gstat.object$data))datadata frame, output of predict.gstatgstat.object object of class gstat, used to extract ids; may be missing if ids is usedXidsDetailsValuecontrast vector or matrix; the number of variables in gstat.object shouldequal the number of elements in X if X is a vector, or the number of rows in X ifX is a matrix.character vector with (selection of) id names, present in dataFrom data, we can extract the (n × 1) vector with multivariable predictions, say y, and its (n × n)covariance matrix V . Given a contrast matrix in X, this function computes the contrast vector isC = X ′ y and V ar(C) = X ′ V X.a data frame containing for each row in data the generalized least squares estimates (named beta.1,beta.2, ...), their variances (named var.beta.1, var.beta.2, ...) and covariances (named cov.beta.1.2,cov.beta.1.3, ...)Author(s)Edzer J. PebesmaReferenceshttp://www.gstat.org/