Data source file formats

Depending how HippoDraw was configured when built, it supports creating a data source by reading a file in several formats.

The file formats supported are

The file may be read using either the File menu on the canvas window or by Python using the Python extension module tutorial.

ASCII file

The HippoDraw application can read and write NTuple data to a plain text file. The format is quite simple. Here is the contents of such a file.


Mark II Z0 scan
Energy	Sigma	binsize	error
 90.73999786  29  0.25999999  5.9000001 
 91.05999756  30  0.23  3.1500001 
 91.43000031  28.39999962  0.25999999  3 
 91.5  28.79999924  0.28999999  5.80000019 
 92.16000366  21.95000076  0.22  7.9000001 
 92.22000122  22.89999962  0.25  3.0999999 
 92.95999908  13.5  0.20999999  4.5999999 
 89.23999786  4.5  0.28  3.5 
 89.98000336  10.80000019  0.27000001  4.5999999 
 90.34999847  24.20000076  0.25999999  3.5999999 

The first line is the title. It can contain any number of spaces and is terminated by the new line character. The second line contains the labels. You can't see it but they are separated by the tab character to allow blanks to be in the labels. The remaining lines are the data, row by row. Any white space can separate the data. The title line and labels line can be missing. The labels can't be pure numbers, or it will be read as data.

FITS files

FITS (Flexible Image Transport System) is the standard astronomical data format endorsed by both NASA and the IAU. If HippoDraw was configured with CFITSIO, then FITS file containing images and binary or ASCII tables are supported. A FITS file can be read with C++ or Python using the FitsController class. The example of Reading and writing FITS files with Python shows how it is done and is available in the examples subdirectory of the installation.

ROOT files

Limited support for reading data from a ROOT file is supported if HippoDraw was configured for ROOT support. The C++ RootNTuple class explains these limitations. A ROOT file can be read with C++ or Python using the RootController class. The example of Using data from a ROOT file with Python shows how it is done and is available in the examples subdirectory of the installation.
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