18.35. R Syntax Summary table for Processing

Module contributed by Matteo Ghetta - funded by Scuola Superiore Sant’Anna

Processing allows a lot of different input and output parameter that can be used in the script body. Here a summary table:

18.35.1. Input parameters

Parameter

Syntax example

Returning objects

vector

Layer = vector

SpatialDataFrame object, default object of rgdal package

vector point

Layer = vector point

SpatialPointDataFrame object, default object of rgdal package

vector line

Layer = vector line

SpatialLineDataFrame object, default object of rgdal package

vector polygon

Layer = vector polygon

SpatialPolygonsDataFrame object, default object of rgdal package

multiple vector

Layer = multiple vector

SpatialDataFrame objects, default object of rgdal package

table

Layer = table

dataframe conversion from csv, default object of read.csv function

field

Field = Field Layer

name of the Field selected, e.g. "Area"

raster

Layer = raster

RasterBrick object, default object of raster package

multiple raster

Layer = multiple raster

RasterBrick objects, default object of raster package

number

N = number

integer or floating number chosen

string

S = string

string added in the box

longstring

LS = longstring

string added in the box, could be longer then the normal string

selection

S = selection first;second;third

string of the selected item chosen in the dropdown menu

crs

C = crs

string of the resulting CRS chosen, in the format: "EPSG:4326"

extent

E = extent

Extent object of the raster package, you can extract values as E@xmin

point

P = point

when clicked on the map, you have the coordinates of the point

file

F = file

path of the file chosen, e.g. «/home/matteo/file.txt»

folder

F = folder

path of the folder chosen, e.g. «/home/matteo/Downloads»

Any of the input could be also OPTIONAL, that means that you have a handy way to tell the script to ignore this parameter.

In order to set an input as optional, you just have to add the string optional before the input, e.g:

##Layer = vector
##Field1 = Field Layer
##Field2 = optional Field Layer

18.35.2. Output parameters

Output parameters take the Input names you gave at the beginning of the script and write the object you want.

Parameter

Syntax example

vector

Output = output vector

raster

Output = output raster

table

Output = output table

file

Output = output file

Nota

for the plot input type, you can save the plot as png directly from the Processing Result Viewer or you can choose to save the plot directly from the algorithm interface.

18.35.3. Examples

In order to better understand all the input and output parameters, please have a look at the R Syntax chapter.