Convert CDL to PDF

A PDF is useful when a CDL listing must be printed, emailed, reviewed without netCDF software, or stored as a fixed record. The correct method depends on whether .cdl contains netCDF CDL text or belongs to an unrelated proprietary application.

What the CDL format is

In scientific computing, CDL means network Common Data form Language, a plain-text representation of a netCDF dataset. It describes dimensions, variables, attributes, and data values; netCDF utilities such as ncdump and ncgen create and process it.

For example, ncdump -h data.nc > data.cdl writes a header-only description, while ncdump data.nc > data.cdl writes the complete dataset. A netCDF CDL file normally contains sections such as netcdf, dimensions:, variables:, and data:. Other engineering, design, and industry applications also use the .cdl extension, so identify the source application before choosing a converter.

What the PDF format is

PDF stores a fixed page layout, including fonts, line wrapping, and print positioning, across operating systems. It is suitable for sharing or archiving a readable CDL listing, but it does not preserve netCDF's machine-readable structure, provide an interactive data viewer, or automatically create charts.

How to convert CDL text to PDF

Using a text editor

1. Open the file in a text editor that handles large files and UTF-8, such as Visual Studio Code, Notepad++, or BBEdit.
2. Choose a monospaced font and disable word wrap. Use landscape orientation, narrower margins, or a smaller font when long declarations and numeric arrays must remain on one line.
3. Print the file with File → Print, select the system PDF printer, and save it as data.pdf. Notepad++ can use a PDF printer installed on Windows; Visual Studio Code may require a printing extension.

LibreOffice Writer is another desktop option: open the file as plain text, retain a monospaced font, verify the import settings, and choose File → Export as PDF. Check the result because an import can change tabs, spacing, or line breaks.

Using the command line

On Linux or macOS, an available fixed-width print workflow is:

enscript -B -f Courier9 -p data.ps data.cdl && ps2pdf data.ps data.pdf

This requires enscript and ps2pdf; install them through the operating system's package manager if they are absent. Inspect the PDF afterward, especially when the source contains very long lines or non-ASCII characters.

Using an online converter

For non-sensitive CDL that is only plain text, a general text-to-PDF service such as CloudConvert or Zamzar may accept a copy renamed from data.cdl to data.txt. Select the TXT-to-PDF conversion, download the result, and verify line wrapping and page breaks. These services are not netCDF-aware and should not receive confidential research data, credentials, or regulated information.

Creating a report from the dataset

To produce a report with metadata, tables, or charts rather than a page image of the source, first reconstruct the netCDF file:

ncgen -o data.nc data.cdl

This succeeds only when the CDL is valid and ncgen supports the file's netCDF features. Open data.nc with Panoply, ncview, or Python using xarray and matplotlib, then use the application's Export or the operating system's PDF printer. The resulting PDF documents the data visually; it is not a replacement for the original CDL or netCDF file.

Quality and compatibility limitations

Printing a complete CDL can create hundreds or thousands of pages when large arrays are included. For metadata documentation, create a smaller source with ncdump -h data.nc > data-header.cdl before printing. PDF conversion does not validate CDL syntax or preserve editable variables, and a PDF viewer cannot regenerate a reliable netCDF dataset from arbitrary layout changes.

Keep the original .cdl file and, when applicable, the generated .nc file with the PDF. If the extension belongs to a proprietary program rather than netCDF, open it in that program and use its own File → Export → PDF command; netCDF utilities and generic text converters may produce meaningless output.