Workflow:How to preserve your 3D data with the French National 3D Repository?
There are two ways to create a repository on the CND3D - the final objective being to keep the data on the servers of the National 3D Data Conservatory.
- Online SIP's creation and manual documentation (1): the data files are uploaded directly to the repository, and all the metadata must then be filled online. This approach is not recommended for large projects with numerous data. (need for Sarah's confirmation).
- Offline SIP's creation and semi-automatic documentation (2): the data files are first organized and documented in the aLTAG3D software - to be installed on the computer. A large part of the required metadata is retrieved automatically on supported file formats: only the descriptive metadata remains to be documented. Once all the information is filled in, aLTAG3D checks the validity of the deposit, and generates a tree structure with the metadata (XML file). This package can be sent via ftp, with Filezilla for example. This second option is therefore preferable because it allows better documentation of the repositories. Furthermore, when the file formats are recognized by the archiving infrastructure CINES, the same SIP can be deposited here.
First method (online SIP's creation)
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Second method (offline SIP's creation)
Step 1: Create the SIP
- Identify the data you want to preserve (see 3D data life cycle for more information)
- Open aLTAG3D, create a new project and save it on your working folder (probably in the folder of the 3D data you want to preserve)
- If you are using the software for the first time, it may be necessary to activate all plugins
- A tree structure of nodes appears. Each box corresponds to a type of information.
- By selecting a box, the metadata appears in the side panel on the right. All required information is framed in red; other information is optional. When information is entered, the red box turns green. The aim of the game is that all boxes turn green to generate the SIP.
- If a node is pulled, a new box is added. Depending on the data to be stored, it is possible to customize the output.
- You can drag and drop the files to be preserved on the box, a huge amount of technical metadata is automatically extracted. You only have to fill a little amount of information.
- Verify the integrity of the project.
- You can generate a rapport of the project ready to be exported
- You can proceed to the creation of the SIP. A few extra information are required, and the the software will copy every files in a new folder, and create some xml file containing metadatas
Step 2: Upload the SIP
- The SIP must be loaded onto the CND3D servers via the FTP protocol. Filezilla can be used.
- If this is the first time, you can request an account and login details from [email@example.com firstname.lastname@example.org]
This workflow is designed to preserve 3D data produced in the framework of cultural heritage documentation, and to semantically enrich them so that they can be harvested in the ecosystem created by the 3D for Humanities Consortium and the HumaNum service.
The concepts of archiving and preservation of digital data should not be confused. Preservation implies that data is stored and populated with a set of metadata on a medium. Archiving brings an additional constraint: as file formats evolve, the files must also be updated to ensure the long-term readability of the content. This costly operation can only be done if the file format is documented and has a validator. As a consequence, only a few file formats can be accepted. Preservation, on the other hand, means keeping the files as they were received, without maintaining the file formats, which is a lighter solution. Although there is no obligation concerning the file formats that can be deposited, we can only recommend that the most universal possible formats be used, which are documented and can be opened with software that is accessible in the medium term.
Preserving files does not only mean putting them on a server or a hard disk, as several dangers can arise. Over time, one can forget that they exist. Then, one can also forget how they were produced, for what purpose. This is important information that allows you to have confidence in the data: this is a key aspect in the reuse of data for scientific research. All this information should be transcribed in the form of metadata. The main advantage of the proposed workflow (compared to archiving) is to format the information so that it can be recognized by the tools developed by the French National 3D Repository (aka "Conservatoire National des Données 3D") and several other search engines ([https://isidore.science/ Isidore, ARIADNE+ and GoTriple) when it will be in place. Thus, from a single point of deposit, data can be retrieved on other platforms.
Evaluation and Review
The workflow has been extensively tested since 2016 by members of the 3D SHS Consortium, and is regularly improved. For any questions or suggestions, please contact email@example.com
For an extensive documentation about the scheme of metadata behind aLTAG3D and the National 3D Repository (in French):
- Dutailly B., Eusèbe S., Grimaud V., Lefèvre N., Quantin M., Tournon S., 2019. L’archivage pérenne des modèles numériques 3D pour les SHS. Consortium 3D SHS, dir. Granier X. hal-02195914
For a more detail approach of the workflow (in French):
- Tournon S., Grimaud V., Dutailly B., Granier X., 2020. Le Conservatoire National des Données 3D SHS. Humanistica 2020, May 2020, Bordeaux, France. hal-02733470