Create as.* functions (for output)

[alexgenin]

After running all the indicators the user is likely to want to export the results to a more standard object like a data.frame (so it can do beautiful plots in ggplot for example).

To do this we need functions that take the output object:

list(variance = list(value = xx, ...), # OR variance = xx
     skewness = list(value = xx, ...), 
     psd = `psd object`, 
     ...) 
(class: c('spatial_indicators', 'list'))

and convert it to something like this

> as.data.frame(indic_object) 

data.frame of x rows and x columns
         replicate value
variance 1            xx
variance 2            yy
variance 3            zz
skewness 1            aa
skewness 2            bb
(etc.)

class: c('data.frame', 'list')

Non numerical indicators cannot fit into this data structure so I suggest dicarding them.

[alexgenin]

Obsolete