# How to interpolate within defined boundaries of a deformed mesh using R?

My goal is to create an interpolation map of some output model results that are mapped on a deformed mesh (from a numerical simulation). The model results are in an x-y plane (representing coordinates) with a variable-z to interpolate, however the coordinates are irregularly spaced and have an upper boundary that should be respected.

I am able to plot exactly what I was using a program called Tecplot, however I can only do one image at a time. Using Tecplot is extremely tedious and thus I would like to automate this in R. Here is what I want:

I am currently using this code below in R to do the same thing however my results are less than ideal and I would like to improve my R code.

Here is my code I am currently using and the non-ideal output of that code:

library(akima)
library(ggplot2)
library(reshape2)

file<-"D:/MIN3P/NoGrowth/1a11/Russ2D_46.gsp"

data<-total[,c(1,3,5)]
names(data)<-c("x","y","z")

#interpolate with akima
inter<-interp(x=data\$x, y=data\$y, z=data\$z,xo=seq(min(data\$x), max(data\$x),   length = 300),yo=seq(min(data\$y), max(data\$y), length = 100),extrap=FALSE)

filled.contour(inter,xlim=c(50,150),ylim=c(5,17),color.palette=colorRampPalette(c("Red", "blue")),xlab = "Distance Across River",ylab = "Elevation", main = "Pressure",key.title = title(main = "Pressure (m)", cex.main = 1))

#contouring with melt and ggplot
df <- melt(inter\$z, na.rm = TRUE)
names(df) <- c("x", "y", "z")
df\$x <- inter\$x[df\$x]
df\$y <- inter\$y[df\$y]

ggplot(data = df, aes(x = x, y = y, z = z)) +
geom_tile(aes(fill = z)) +
stat_contour() +
ggtitle("Pressure") +
xlab("Distance Across River") +
ylab("Elevation") +
scale_fill_continuous(name = "Pressure (m)",low = "Red", high = "blue") +
theme(plot.title = element_text(size = 25, face = "bold"),
legend.title = element_text(size = 15),
axis.text = element_text(size = 15),
axis.title.x = element_text(size = 20, vjust = -0.5),
axis.title.y = element_text(size = 20, vjust = 0.2),
legend.text = element_text(size = 10))

Here are my non-ideal results with the Akima package:

Here are my non-ideal results with ggplot:

How can I create an image similar to the one from Tecplot but using R? Notice that in the plots from ggplot and from Akima, the top boundary shape is completely obscured and I want that feature to stand out, and for the interpolation to respect the shape of the top as it is a very important feature.

• Could you please recover the link to the raw data ? – César Arquero Mar 7 at 9:35