FITS table to TTree conversion

table2tree()
{
// A FITS table is read from a FITS file, and converted into 
// a ROOT tree. The tree is displayed with its TreeViewer.

   // read one table extension from the FITS file
   // SPI.-FEE3-HRW is the extension name of the FITS table
   TFTable * table = TFReadTable("spi_raw_acs.fits.gz", "SPI.-FEE3-HRW");
   if (table)
      {
      // convert the table into a TTree
      TTree * tree = table->MakeTree();
      delete table;

      // view the data
      tree->StartViewer();     
      }
}

FITS table to TGraph conversion

table2graph()
{
// A FITS table is read from a FITS file, and converted into 
// a ROOT TGraph. The graph is displayd.


   // read one table extension from the FITS file
   // SPI.-FEE8-HRW is the extension name of the FITS table
   TFTable * table = TFReadTable("spi_raw_acs.fits.gz", "SPI.-FEE8-HRW");
   if (table)
      {
      // use the two columns PACK_TIME and FEE65 of the table 
      // to crate a TGraph. 
      TGraph * graph = table->MakeGraph("PACK_TIME", "FEE65");
      delete table;

      // display the data
      graph->Draw("AL");     
      }
}

FITS image to TH2D conversion

image2histogram()
{
// read an FITS image, convert it into a 
// ROOT histogram and display it

   // The image we want to display is the extension
   // SPI.-SKY.-IMA in the image.fits file.
   TFFloatImg * img = TFReadImage("image.fits", "SPI.-SKY.-IMA");
   if (img == NULL)
      {
      TFError::PrintErrors();
      return;
      }

   // create a TH2D histogram and display it
   TH2D * hist = img->MakeHisto();
   hist->Draw("surf4");

}

Image Display

image_display1()
{
// create an astronomical image display directly from a FITS file
// and display it.

   // The image we want to display is the third HDU in the file
   // image.fits.
   AstroImage * disp = new AstroImage("image.fits", NULL, 3);

   // read a color palette, it was written to the file via the
   // color editor (Save button)
   TFile *fpal = new TFile("image.pal.root", "READ");
   TImagePalette *palette = (TImagePalette*)fpal->Get("TImagePalette");
   delete fpal;

   // use the palette for this image
   disp->SetPalette(palette);
   delete palette;

   // draw the image and open its palette editor
   disp->Draw();
   disp->StartPaletteEditor();
}

image_display2()
{
// read an FITS image, modify it slightly and display the 
// result.

   // The image we want to display is the extension SPI.-SKY.-IMA
   // in the image.fits file.
   TFFloatImg * img = TFReadImage("image.fits", "SPI.-SKY.-IMA");
   if (img == NULL)
      {
      TFError::PrintErrors();
      return;
      }

   // get the size of image. We know it has two dimensions
   UInt_t size[2];
   img->GetSize(size);

   // cut all values above 8
   for (UInt_t x = 0; x < size[1]; x++)
      for (UInt_t y = 0; y < size[0]; y++)
         if ( (Float_t)((*img)[y][x]) > 8.0)
            (*img)[y][x] = 8.0;

   // open a window and open the status bar to display the 
   // coordinates and value of the image pixel at the mouse position
   TCanvas * win = new TCanvas("image", "SPI", 100, 100, 550, 524);
   win->ToggleEventStatus();

   // create the image display for the just read and slightly
   // modified image
   AstroImage * disp = new AstroImage(img);

   // we don't need the image any more
   delete img;

   // draw the image
   disp->Draw();
}