1Fitstopnm User Manual(0) Fitstopnm User Manual(0)
2
3
4
6 fitstopnm - convert a FITS file into a PNM image
7
8
10 fitstopnm [-image=N] [-scanmax] [-printmax] [-min=f] [-max=f] [-omax‐
11 val=N [FITSfile]
12
13 Minimum unique abbreviation of option is acceptable. You may use dou‐
14 ble hyphens instead of single hyphen to denote options. You may use
15 white space in place of the equals sign to separate an option name from
16 its value.
17
18
19
21 This program is part of Netpbm(1).
22
23 fitstopnm reads a FITS (Flexible Image Transport System) file as input
24 and produces a PPM image if the FITS file consists of 3 image planes
25 (NAXIS = 3 and NAXIS3 = 3), or a PGM image if the FITS file consists of
26 2 image planes (NAXIS = 2), or if you specify the -image option.
27
28 The program tells you what kind of PNM image it is writing.
29
30
31
33 -image=N
34 This is for FITS files with three axes. The assumption is that
35 the third axis is for multiple images, and this option lets you
36 select which one you want. -omaxval=N
37
38 This is the maxval that the output PNM image is to have.
39
40 By default, the maxval is the least possible to retain all the
41 precision of the FITS input. That means the difference between
42 the highest and lowest sample value in the input. If the values
43 range from -5 to 100, for example, the default maxval would be
44 106 and each PNM sample value would correspond to one FITS sam‐
45 ple value.
46
47 For a FITS input with floating point sample values, the preci‐
48 sion is essentially unlimited, so this is not possible. In that
49 case, the default maxval is simply 255.
50
51 This option was new in Netpbm 10.39 (June 2007). Before that,
52 the output maxval is always the default.
53
54
55 -min=float
56
57 -max=float
58
59 You can use these options to override the min and max values as
60 read from the FITS header or the image data if the header has no
61 DATAMIN and DATAMAX keywords.
62
63
64 -scanmax
65 Use this option to force the program to scan the data even when
66 the header has DATAMIN and DATAMAX.
67
68
69 -printmax
70 With this option, the program just prints the min and max values
71 and quits without doing its normal job.
72
73 This is for use in shell programs. Example:
74
75 eval 'fitstopnm -printmax $filename | \
76 awk {min = $1; max = $2} \
77 END {print "min=" min; " max=" max}'
78
79
80
81
83 Pixel Order
84 You may need to pass the output of fitstopnm through pamflip -topbot‐
85 tom. See pamtofits ⟨pamtofits.html#pixelorder⟩
86
87
88
90 pamtofits(1), pamflip(1), pgm(1) FITS(1)
91
92
94 Copyright (C) 1989 by Jef Poskanzer, with modifications by Daniel
95 Briggs (dbriggs@nrao.edu) and Alberto Accomazzi (alberto@cfa.har‐
96 vard.edu).
97
98
99
100netpbm documentation 22 May 2007 Fitstopnm User Manual(0)