Projects are a basic unit of data organization in the HCA Data Coordination Platform (HCA DCP). Project contributors contribute raw sequencing and associated files along with rich metadata describing:
The HCA Data Explorer lists all projects on its home page along with key project metadata. The project list is filterable by the metadata values.
Figure 1: The Data Explorer's projects tab lists the projects making up the DCP.
Selecting a project title on the project list takes you to the project's detail page.
Figure 2: A project detail page showing the various information and downloads available for the project.
The project detail page contains:
For each project, the HCA DCP maintains a project specific tsv file containing the full project metadata. The tsv contains a row for each file in the project and columns for each metadata property. Meanings of the metadata properties are listed in the HCA Metadata Dictionary.
The metadata tsv file gives a flattenedjapan-science-meeting-tutorial.md representation of the projects metadata graph that can be sorted and filtered using standard spreadsheet or data manipulation tools.
The "Project Downloads" section of the project details page contains a link to download the project metadata file.
Figure 3: The "Project Downloads" section of the project details page.
Metadata file sizes vary across projects but will generally be between 1 and 100 megabytes.
The tsv file is named after the project and includes the date and time the file was created. For example:
CD4+ cytotoxic T lymphocytes 2019-07-19 19.09.tsv
A partial example of a tsv file is listed below:
Figure 4: A partial view of a project's metadata tsv file.
For projects with supported library construction approaches, the project detail page will also contain a link to download expression matrices pre-generated for the project by the HCA Matrix Service.
The rows in the expression matrix represent cells, columns give the expression value for the column's gene.
Figure 5: A partial view of a project's expression matrix in csv format.