# GGplot - Stat - (Statistical transformation|Statistic)

The Statistical transformation (stat). Multiple layers, statistical transformation.

It's often useful to transform your data before plotting, and that's what statistical transformations do.

## Stat, geom relation

Every geom function has a default statistic:

And every statistic function has a default geom.

• stat_…

## List of statistic

Some statistics produce new data frame variables in the data. stat_bin produces count and density.

## Management

### Mapping a new stat to an aesthetic

Some statistics produce new data frame variables in the data.

Example: stat_bin produces count and density.

To map an aesthetic to one of the new stat variables, surround it with ..

``````p = ggplot(diamonds, aes(x=price))
p + geom_histogram(aes(y = ..density..))
p + geom_histogram(aes(colour = ..count..))```
```

### Separation of statistics and geometric elements

``````p <- ggplot(diamonds, aes(x=price))
p + stat_bin(geom="bar") # Equivalent to p + geom_histogram()
p + stat_bin(geom="area")
p + stat_bin(geom="point")
p + stat_bin(geom="line")```
```

Discover More
GGplot - Coordinate System

coordinate system control how the two coordinates aesthetics work together (default: Cartesian) Others: coord_flipcoord_flip() - Flip x and y coord_map() coord_polar() They Occur after statistics...
GGplot - Layer (data + mapping + geom + stat + position)

Layer = data: The data frame (in a variable or a function, if null inherited) + mapping: Mapping data to geom properties (ie aesthetics) + geom : The geometric object to use display the data +...
Ggplot - Geom (geometric objects) - type of plot

Geom is a short for geometric objects that describe the type of plot produced. point for point (to create a scatterplot) line for a line ... The geom_... functions are shortcuts for a layer set...
Ggplot - Smooth (Geom_Smooth|Stat_Smooth)

smoothing in Ggplot Smooth (Smoothed conditional means) is seen as a: stat - mean calculation and a geom - line or point geom_smoothstat_smooth() is a layer and an alias of geom_smoothgeom_smooth()....
R - Ggplot

ggplot is a graphic library that follows the 0387245448grammar of graphics. charts are made of : layers that are made of: Data geometries: the graphical element...