MRC Data File Header Locations

Location Name Content 1=Integer,
2=Real,
3=Char
1NX # of columns (pixels) per line 1
2NY # of rows per image 1
3NZ # of sections (slices/planes) in volume (=1 for an image) 1
4MODE Data type 1
0 8 bit signed byte Image/volume (-128-->127)
6 8 bit unsigned byte Image/volume (0-->255)
1 16 bit signed integer Image/volume
2 32 bit real Image/volume
3 16 bit complex Fourier transform, (Unsupported)
4 32 bit complex Fourier transform, (Unsupported)
5 NXSTART # of first column in map 1
6 NYSTART # of first row in map 1
7 NZSTART # of first slice/section in map 1
8 MX # of intervals along X 1
9 MY # of intervals along Y 1
10 MZ # of intervals along Z (>1 for stack) 1
11 CELLAX X Cell dimension in Angstroms (pixel size * NX) 2
12 CELLAY Y Cell dimension in Angstroms (pixel size * NY) 2
13 CELLAZ Z Cell dimension in Angstroms (pixel size * NZ) 2
14 CELLBX X Cell angle in degrees (PHI) 2
15 CELLBY Y Cell angle in degrees (THETA) 2
16 CELLBZ Z Cell angle in degrees (PSI) 2
17 MAPC Axis corresponding to columns (Should be == 1) 1
18 MAPR Axis corresponding to rows (Should be == 2) 1
19 MAPS Axis corresponding to sections (Should be == 3) 1
20 DMIN Minimum density value 2
21 DMAX Maximum density value 2
22 DMEAN Mean density value 2
23 ISPG Space group number (Images == 0, volume == 1 ) 1
24 NSYMBT # of bytes used for symmetry data (0 or 80) 1
25 IMGSTATS SPIDER defined, Image for stats in: 20,21,22 & 55 1
26 CAXIS SPIDER defined, Data origin & handedness 3
27 EXTTYP Extension type, currently: 'MRCO' 3
28 IVERSION Version number, currently: 20140 1
29-41EXTRA Extra user defined storage space 1
42 IANGLE SPIDER defined, # of angles in locations: 43..48 1
43 ANG1 PHI (SPIDER & IMOD defined location) 2
44 ANG2 THETA (SPIDER & IMOD defined location) 2
45 ANG3 PSI (SPIDER & IMOD defined location) 2
46 ANG4 PHI1 (SPIDER & IMOD defined location) 2
47 ANG5 THETA1 (SPIDER & IMOD defined location) 2
48 ANG6 PSI1 (SPIDER & IMOD defined location) 2
49 EXTRA Extra user defined storage space 1
50 ORX X origin for transforms 2
51 ORY Y origin for transforms 2
52 ORZ Z origin for transforms 2
53 MAP Character string 'MAP ' identifies file type 3
54 MACHST Machine stamp 1
55 RMS RMS Deviation of map from mean density 2
56 NLABL # of labels in use 1
57-256 LABEL Up to ten 80-character text labels 3

Page updated: 24 Nov. 2019