I am using the R programming language. I made the following 3D plot in R:

```
# set seed for reproducibility
#load libraries
set.seed(123)
library(dplyr)
library(plotly)
#create data
n <- 3
my_grid <- expand.grid(i1 = 1:n, i2 = 1:n)
my_grid$final_value = with(my_grid, sin(i1) + cos(i2) )
#make plot
plot_ly() %>%
add_trace(data = my_grid, x=my_grid$i1, y=my_grid$i2, z=my_grid$final_value, type='mesh3d') %>%
add_surface(
z = my_grid %>% as.matrix(),
surfacecolor = my_grid,
cauto=F,
cmax=max(my_grid$final_value),
cmin=min(my_grid$final_value)
)
```

This produces the following plot:

As expected, this plot seems to be very logical : it shows a 3D surface where x = i1, y = i2, z = final_value, and the color of the plot is according "final_value".

**Problem:** If I try to add some more data to the grid and then create the plot:

```
#create more data
n <- 50
my_grid <- expand.grid(i1 = 1:n, i2 = 1:n)
my_grid$final_value = with(my_grid, sin(i1) + cos(i2) )
#make plot
plot_ly() %>%
add_trace(data = my_grid, x=my_grid$i1, y=my_grid$i2, z=my_grid$final_value, type='mesh3d') %>%
add_surface(
z = my_grid %>% as.matrix(),
surfacecolor = my_grid,
cauto=F,
cmax=max(my_grid$final_value),
cmin=min(my_grid$final_value)
)
```

Not only does this graph look "strange", but the "y-coordinate" (1697) within the hover text is displaying a value which is not present within the original data:

```
#display histogram of values
par(mfrow=c(1,3))
hist(my_grid$i1)
hist(my_grid$i2)
hist(my_grid$final_value)
```

** Question:** In the above histogram, a value of "1697" does not appear in any of the variables. So how is it possible that such a large value is displayed within the plotly diagram?

Thanks