This function takes distance in km and converts it into meters, the
units generally used by geographic operations in `R`

. This is a trivial
conversion, but this functions ensures that no zeroes are lost along the way!

## Arguments

- x
the number of km

## Value

the number of meters

## Examples

```
km2m(10000)
#> [1] 1e+07
km2m(1)
#> [1] 1000
```