graph.rbfST | R Documentation |
Function for plotting the RMSPE for several values of the smoothing parameter
eta with the same dataset. A curve is fitted to the points, and
then the optimal eta that provides the smallest RMSPE is determined from the
curve, by the optimize
function from the stats
package.
graph.rbfST(formula, data, eta.opt, rho.opt, n.neigh, func, np, xo, eta.dmax, rho.dmax, P.T, iter, ...)
formula |
formula that defines the dependent variable as a linear model of independent variables (covariates or the principal coordinates); suppose the dependent variable has name z_{st}, for a rbfST detrended use z_{st} |
data |
SpatialPointsDataFrame: should contain the spatio-temporal dependent variable, independent variables (statics and/or dynamics), spatial coordinates and the time as an integer or numerical variable. |
eta.opt |
logical, indicating whether the parameter eta should be regarded as fixed (eta.opt = FALSE) or should be estimated (eta.opt = TRUE) |
rho.opt |
logical, indicating whether the parameter rho should be regarded as fixed (rho.opt = FALSE) or should be estimated (rho.opt = TRUE) |
n.neigh |
number of nearest observations that should be used for a rbfST prediction, where nearest is defined in terms of the spatio-temporal locations |
func |
function to be optimized. The following radial basis function spatio-temporal model types are currently available: gaussian "GAU", exponential "EXPON", trigonometric "TRI", thin plate spline "TPS", completely regularized spline "CRS", spline with tension "ST", inverse multiquadratic "IM", and multiquadratic "M", are currently available |
np |
number of points, where the radial basis function spatio-temporal is calculated |
xo |
starting point for searching the optimum. Defaults to c(0.5, 0.5), eta and rho respectively. Use this statement only if eta and rho are equal to TRUE. |
eta.dmax |
maximum value of the range of the eta parameter that will be evaluated by the |
rho.dmax |
maximum value of the range of the rho parameter that will be evaluated by the |
P.T |
logical. Print table (TRUE) or not (FALSE). Default P.T=NULL. |
iter |
The maximum allowed number of function evaluations. |
... |
further parameters to be passed to the minimization functions |
Returns a graph that describes the behavior of the optimized eta or rho parameters and a table of values associated with the graph including optimal smoothing eta or rho parameters. If both eta and rho are FALSE simultaneously then the function returns a list with the best value obtained from the combinations smoothing eta and rho parameters and a lattice plot of class "trellis" with RMSPE pixel values associated with combinations of eta and rho parameters. Finally, if both eta and rho are TRUE, the function will return a list with the best combination of values of the smoothing eta or rho parameters and the RMSPE associated with these.
Johnston, K., Ver, J., Krivoruchko, K., Lucas, N. (2001). Using ArcGIS Geostatistical Analysis. ESRI.
Melo, C. E. (2012). Analisis geoestadistico espacio tiempo basado en distancias y splines con aplicaciones. PhD. Thesis. Universitat de Barcelona. 276 p. [link]
rbfST
, rbfST.cv
## Not run: data(croatiadb) coordinates(croatiadb)<-~x+y # optimizing eta graph.rbfST(MTEMP~X1+X2+X3+X4+X5+X6+X7+X8+X9+X10, data=croatiadb, eta.opt=TRUE, rho.opt=FALSE, n.neigh=30, func="TPS", np=40, eta.dmax=2, P.T=TRUE) # optimizing rho graph.rbfST(MTEMP~X1+X2+X3+X4+X5+X6+X7+X8+X9+X10, data=croatiadb, eta.opt=FALSE, rho.opt=TRUE, n.neigh=30, func="M", np=20, rho.dmax=2, P.T=TRUE) # optimizing eta and rho tps.lo <- graph.rbfST(MTEMP~X1+X2+X3+X4+X5+X6+X7+X8+X9+X10, data=croatiadb, eta.opt=TRUE,rho.opt=TRUE, n.neigh=25, func="TPS", eta.dmax=0.2, rho.dmax=0.2, xo=c(0.1,0.1), iter=50) tps.lo # best combination of eta and rho obtained # lattice of RMSPE values associated with a range of eta and rho, without optimization tps.la <- graph.rbfST(MTEMP~X1+X2+X3+X4+X5+X6+X7+X8+X9+X10, data=croatiadb, eta.opt=FALSE, rho.opt=FALSE, n.neigh=30, func="TPS", np=10, eta.dmax=0.2, rho.dmax=0.2) tps.l$table # best combination of eta and rho obtained tps.l$spplot # lattice of RMSPE ## End(Not run)
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