The R Statistical Raster Data Reader/Writer allows FME to read and write data in the R rasterfile format.
Overview
R is a language and environment for statistical computing and graphics. R files store data as binary or ASCII workspace files that may store a number of objects.
Reader Overview
Using the raster package within R allows raster datasets to be manipulated, the package’s native file format is called rasterfile.
An R rasterfile dataset consists of a header file (.grd) and a sequential binary value data file (.gri), and FME requires both of these files to be present. The header file (.grd) must be provided to FME, while the accompanying data file (.gri) is automatically found in the folder.
Writer Overview
FME considers a dataset to be a folder name.
The names of the R rasterfile output files written to the output dataset folder are determined from the FME Feature Type. The folder does not have to exist before the translation occurs. Any existing files in the folder which have the same name are overwritten with the new feature data. The R rasterfile writer distinguishes duplicate output files by appending numbers to the filenames.
Palette Support
In rasterfile, color support is offered via palettes. Both RGB and RGBA palettes will be read; and on write, they will be created.
String palettes can be read and will be conserved when writing to R rasterfile. Note that while string palettes and RGB/RGBA palettes can coexist and be written to rasterfile, an RGB/RGBA palette will be treated as standard string palettes when read using FME. In other words, if a hypothetical R rasterfile dataset myRaster.grd is written with an RGB palette and a string palette, when reading myRaster.grd the RGB palette will become three string palettes red, green, and blue. The original string palette will be read as expected.
FME Raster Features
FME raster features represent raster data and use several concepts that are unlike those used in the handling of vector data.
For comprehensive information about how FME processes raster data, see Rasters.