17.33. 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:

17.33.1. 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: "EPGS: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

17.33.2. 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


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.

17.33.3. Examples

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