HTRC provides access to data from the HathiTrust corpus in several forms across its suite of tools and services for computational text analysis. Data is periodically synced from HathiTrust, but not all HTRC tools and services are updated on the same schedule. Additionally, copyright, user agreements, and security concerns impact data availability and format.
HTRC algorithms and HTRC Data Capsules have the capability of analyzing the entire HathiTrust corpus, and additionally make use of each volume’s MARC bibliographic and METS metadata. Both the HTRC algorithms and Capsule-environments draw from the HTRC Data API described below.
The HTRC makes available also two datasets, the HTRC Extracted Features Dataset and a dataset of Word Frequencies in English Language Literature, 1700-1922. HTRC Extracted Features includes metadata and extracted page-level data (words and word counts) for 13.7 million volumes.
HathiTrust+Bookworm visualizes data for 15.7 million volumes.
HathiTrust text data
The following table disambiguates textual data access, including availability and format, within the HTRC ecosystem.
|Tool or service|
# volumes (as of 3/18)
|rights status||data access mechanism||file format||data format||permissions required|
|HTRC Analytics algorithms||5.9 million||All||Via HTRC Workset; researcher runs tool without accessing underlying data||(no file access)|
Uncorrected OCR text data; only results are exposed to researcher (not the underlying data)
|HTRC Analytics account|
|HT+Bookworm tool||13.7 million||All||Via web-interface; researcher visualizes data without accessing underlying data||(no file access)||Unigrams (single words), based on HTRC Extracted Features dataset; underlying data not exposed to researcher||(none)|
|HTRC Data Capsule||5.9 million||Public domain for everyone; In-copyright limited to affiliates of HT member institutions upon approval of request||HTRC Data API||Zipped text files in PairTree directory structure||Uncorrected OCR text data||HTRC Analytics account|
|HTRC Extracted Features dataset||15.7 million||All||rsync||JSON files in PairTree directory structure||Volume- and page-level metadata and part-of-speech tagged page-level "bags of words"||(none)|
|HathiTrust custom dataset||6 million, dependent on institutional agreements||Public domain; accessibility of Google-digitized volumes dependent on whether researcher's home institution has signed agreement||rsync|
Zipped text files in PairTree directory structure
|Uncorrected OCR text data||Custom dataset request application|
Building a workset/dataset of HathiTrust text data
- Search and select volumes to build a collection in HathiTrust. Import to HTRC as a workset to use with algorithms or call data into your Capsule using the HTRC Workset Toolkit.
- Query the HathiTrust Bibliographic API.
- Utilize the HathiFiles.
- Need more help? HTRC can help you build a list of volume IDs to analyze. Contact email@example.com.
HT and HTRC APIs
This table outlines the differences between the HTRC Data API and HathiTrust Data API. As a researcher-accessible service, HTRC Data API functions within the HTRC Data Capsules environment.
HTRC Data API
HathiTrust Data API
|purpose||to provide access to HT tex data within and HTRC Data Capsule AND to serve high-performance large-scale algorithms and programs (not user-accessible)||to provide public users some volume retrieval capabilities|
|use||In-capsule via the HTRC Workset Toolkit||Get more information from HathiTrust|
|bulk retrieval of volumes||yes||no|
|metadata available||METS||METS, MARC|