R2 error recovery

Author: MarkusLoew

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: MyEllipsefit
 Title: Uses the conicfit package to fit an ellipse, convenience function with an opional ggplot2 layer
-Version: 0.0.4.0
+Version: 0.0.4.2
 Authors@R: person("Markus", "Loew", email = "[email protected]", role = c("aut", "cre"))
 Description: Uses \code{conicfit} to calculate an ellipse to fit data. Convenience package to provide ellipsis parameters (axes, angle, area, and more). Provides a layer function for ggplot2 to visualise ellipses. See helpfile and example for differences between \code{car::ellipse} and this approach.
 Depends:

NEWS

@@ -1,3 +1,9 @@
+MyEllipsefit 0.0.4.2
+----------------------------------------------------------------
+
+* Conditional calculation of R2, gives NA for missing data 
+instead of stopping
+
 MyEllipsefit 0.0.4.0
 ----------------------------------------------------------------
 

R/Ellipsefit.R

@@ -70,13 +70,17 @@ Ellipsefit <- function(data, x, y, coords = FALSE, bbox = FALSE) {
 
 
 	# calculate R2
-	my.fit <- conicfit::fit.ellipseLMG(xy, 
+	my.fit <- try(conicfit::fit.ellipseLMG(xy, 
                      ParGini = geopara, 
-                     LambdaIni = 1)
-	SSres <- my.fit$RSS
-        SStot <- stats::var(y, na.rm = TRUE)
-        R2    <- 1 - (SSres / SStot)
-       
+                     LambdaIni = 1))
+	if (inherits(my.fit, "try-error")) {
+	   R2 <- NA
+	} else {
+	   SSres <- my.fit$RSS
+           SStot <- stats::var(y, na.rm = TRUE)
+           R2    <- 1 - (SSres / SStot)
+	}
+	       
         geopara.out <- as.data.frame(t(geopara))
         geopara.out$R2 <- R2
         names(geopara.out) <- c("Centerpoint_X", "Centerpoint_Y", 

README.md

@@ -24,6 +24,7 @@ Fit parameters are:
 * The distance from the center to the perimenter along the minor axis. 
 * The tilt angle of the ellipse. 
 * The area of the ellipse. 
+* The goodnes-of-fit R2 of the ellipse fit.
 
 If *coords = TRUE*, returns a data frame with the coordinates of the ellipse in addition.