Logo ROOT   6.08/07
Reference Guide
FITS_tutorial2.C File Reference

Detailed Description

Open a FITS file whose primary array represents a spectrum (flux vs wavelength)

void FITS_tutorial2()
{
printf("\n\n--------------------------------\n");
printf("WELCOME TO FITS tutorial #2 !!!!\n");
printf("--------------------------------\n");
printf("We're gonna open a FITS file that contains the\n");
printf("primary HDU and a little data table.\n");
printf("The primary HDU is an array of 2 rows by 2040 columns, and\n");
printf("they represent a radiation spectrum. The first row contains\n");
printf("the flux data, whereas the second row the wavelengths.\n");
printf("Data copyright: NASA\n\n");
if (!gROOT->IsBatch()) {
//printf("Press ENTER to start..."); getchar();
}
TString dir = gSystem->DirName(__FILE__);
// Open primary HDU from file
TFITSHDU *hdu = new TFITSHDU(dir+"/sample2.fits");
if (hdu == 0) {
printf("ERROR: could not access the HDU\n"); return;
}
printf("File successfully open!\n");
// Dump the HDUs within the FITS file
// and also their metadata
//printf("Press ENTER to see summary of all data stored in the file:"); getchar();
hdu->Print("F+");
printf("....................................\n");
printf("We are going to generate a TGraph from vectors\n");
//printf("within the primary array. Press ENTER to continue.."); getchar();
TVectorD *Y = hdu->GetArrayRow(0);
TVectorD *X = hdu->GetArrayRow(1);
TGraph *gr = new TGraph(*X,*Y);
// Show the graphic
TCanvas *c = new TCanvas("c1", "FITS tutorial #2", 800, 800);
gr->Draw("BA");
// Clean up
delete X;
delete Y;
delete hdu;
}
Author
Claudi Martinez

Definition in file FITS_tutorial2.C.