volcano is a standard data set that comes with R. It includes topographical information about a volcano in New Zealand in matrix format.

library(plotly)
data(volcano)
str(volcano)

##  num [1:87, 1:61] 100 101 102 103 104 105 105 106 107 108 ...

dim(volcano)

## [1] 87 61

We can use plotly to show it as a heatmap:

plot_ly(z=~volcano,type="heatmap")

But we can also make a nice 3d surface plot. Neat, huh?

plot_ly(z=~volcano,type="surface")