Step 4: PDF retrieval

The step of PDF retrieval refers to the activities to acquire PDF documents (or documents in other formats) as well as to ascertain or improve their quality. It should ensure that PDF documents correspond to their associated metadata (no mismatches), that they are machine readable (OCR and semantically annotated), and that unnecessary materials (such as cover pages) are removed.

PDFs are stored in the data/pdfs directory. Per default, PDF documents are not versioned by git to ensure that CoLRev repositories can be published without violating copyright restrictions.

It is recommended to share PDFs through file synchronization clients and to create a symlink pointing from the colrev-repository/data/pdfs to the respective directory used for file sharing.

PDF retrieval is a high-level operation consisting of the following operations:

• The pdf-get operation, which retrieves PDFs from sources like the local_index or unpaywall. It may refer users to pdf-get-man as the manual fallback when the record state is set to pdf_needs_manual_retrieval.

• The pdf-prep operation, which refers to the preparation of PDF documents. It may refer users to pdf-prep-man as the manual fallback when the record state is set to pdf_needs_manual_preparation.

To start the pdfs operation, run:

colrev pdfs

Operations

• colrev pdf-get
• colrev pdf-prep