The "byte skip: 62" line instructs nrrd to start getting the raw data 62 bytes from the start. If there were lines of ASCII header to skip (such as a VTK header), the field would instead be "line skip: ". Not all the fields used above are absolutely needed; for the curious, here is a minimalist header:NRRD00.01 content: engine type: uchar dimension: 3 sizes: 256 256 110 labels: "x" "y" "z" spacings: 1.0 1.0 1.0 data file: ./engine.den byte skip: 62 encoding: raw
NRRD00.01 type: uchar dimension: 3 sizes: 256 256 110 data file: ./engine.den byte skip: 62 encoding: raw
project engine.den.nhdr 2 2 engine.den-maxZ.pgm
project engine.den.nhdr 1 2 engine.den-maxY.pgm
crop engine.den.nhdr 59 207 20 227 0 M engine-crop.nrrd
project engine-crop.nrrd 2 2 engine-crop-maxZ.pgm
The nrrdSave() function of nrrd interprets this filename auto-magically, putting the header information in a small ASCII file called "engine-crop.nhdr", while putting all the raw data with no header whatsoever in seperate file called "engine-crop.raw".crop engine.den.nhdr 59 207 20 227 0 M engine-crop.nhdr