github.com/astrogo/cfitsio@v0.1.0/examples/go-cfitsio-imlist/main.go (about)

     1  package main
     2  
     3  import (
     4  	"flag"
     5  	"fmt"
     6  	"os"
     7  
     8  	fits "github.com/astrogo/cfitsio"
     9  )
    10  
    11  func main() {
    12  	flag.Usage = func() {
    13  		const msg = `Usage: go-cfitsio-imlist filename[ext][section filter] 
    14  
    15  List the the pixel values in a FITS image 
    16  
    17  Example: 
    18    imlist image.fits                    - list the whole image
    19    imlist image.fits[100:110,400:410]   - list a section
    20    imlist table.fits[2][bin (x,y) = 32] - list the pixels in
    21           an image constructed from a 2D histogram of X and Y
    22           columns in a table with a binning factor = 32
    23  `
    24  		fmt.Fprintf(os.Stderr, "%v\n", msg)
    25  		flag.PrintDefaults()
    26  	}
    27  
    28  	flag.Parse()
    29  	if flag.NArg() != 1 {
    30  		flag.Usage()
    31  		os.Exit(1)
    32  	}
    33  
    34  	fname := flag.Arg(0)
    35  	f, err := fits.Open(fname, fits.ReadOnly)
    36  	if err != nil {
    37  		panic(err)
    38  	}
    39  	defer f.Close()
    40  
    41  	hdu := f.CHDU()
    42  	hdr := hdu.Header()
    43  
    44  	if len(hdr.Axes()) > 2 || len(hdr.Axes()) == 0 {
    45  		fmt.Printf("Error: only 1D or 2D images are supported\n")
    46  		os.Exit(1)
    47  	}
    48  
    49  	axes := hdr.Axes()
    50  
    51  	var data []float64
    52  	err = hdu.Data(&data)
    53  	if err != nil {
    54  		panic(err)
    55  	}
    56  
    57  	// default output format string
    58  	hdformat := " %15d"
    59  	format := " %15.5f"
    60  	if hdr.Bitpix() > 0 {
    61  		hdformat = " %7d"
    62  		format = " %7.0f"
    63  	}
    64  	// column header
    65  	fmt.Printf("\n      ")
    66  	row := int(axes[0])
    67  	for ii := 0; ii < row; ii++ {
    68  		fmt.Printf(hdformat, ii)
    69  	}
    70  	fmt.Printf("\n")
    71  
    72  	// loop over all rows
    73  	for jj := 0; jj < int(axes[1]); jj++ {
    74  		fmt.Printf(" %4d ", jj)
    75  		for ii := 0; ii < row; ii++ {
    76  			fmt.Printf(format, data[row*jj+ii])
    77  		}
    78  
    79  		fmt.Printf("\n")
    80  	}
    81  	if err != nil && err != fits.END_OF_FILE {
    82  		panic(err)
    83  	}
    84  }