Quick Guide B: NCAS Image

What is the NCAS Image Standard?

The aim of the standard is to ensure that NCAS’s publicly-accessible image products - e.g. photos taken by automatic cameras and standard data plots - are as traceable, self-explaining, and scientifically-exploitable as its data files. In short, it covers the who, what, where, when, and why of the images. NCAS-IMAGE exploits the capacity of digital image files to have metadata fields embedded within them. This is the same capacity that digital cameras exploit to record details of image-capture settings. The standard can be applied to a wider range of image file types than just photographs.

When to Use it

It is particularly important to apply the standard to images that represent a primary NCAS data product, e.g. photos taken by automatic cameras that are operated as part of a field campaign or a long term measurement programme. It’s also advisable to apply it to images that represent secondary NCAS data products if they are intended to be publicly-accessible, e.g. standard data plots.

How to use it

Application of the standard relies on command-line ExifTool software, which can be run on Linux, MacOS, and Windows computers. A python-based handler allows metadata to be applied from templates that allow substitution fields (since it’s typically only the date-time information that varies from file to file). In the case of automatic cameras, this means that metadata can be added immediately after a photo is captured.

In addition to ExifTool software and the python-based handler, some image viewing applications can be used to display the embedded metadata fields. The Linux app Eye of GNOME is one of the best from this point of view. It can be used within the KDE as well as the GNOME desktop environment.

Tools

ExifTool command-line software

python-based ExifTool handler

Eye of GNOME Linux image viewing app

Further Details

NCAS-IMAGE has been designed to emulate NCAS-GENERAL. However, since arbitrarily-named metadata fields cannot be embedded within image files (at least without access to proprietary software), NCAS-IMAGE has made of use of the following two metadata standards wherever possible:

You can see the full NCAS Image standard at:

Hooper, David A., Brooks, Barbara J., Garland, Wendy E., & Parton, Graham A. (2022). The National Centre for Atmospheric Science Image Metadata Standard (NCAS-IMAGE) version 1.0 (1.0). Zenodo. https://doi.org/10.5281/zenodo.6368295