Overlays Capture Architecture (OCA) is an international open standard for writing data schemas. Schemas are a type of documentation that describe the structure and rules for a dataset. The OCA standard is a machine-readable schema standard that is hosted by the Human Colossus Foundation.
Agri-food Data Canada at the University of Guelph has developed the OCA Composer as a tool to help researchers document their data using the OCA standard. The OCA Composer runs in a web browser and presents a graphical user interface that guides users through the process of authoring their own schemas describing their datasets.
You can learn more about schemas and see an implementation of OCA Composer live at the Semantic Engine.
The OCA Composer is written in React and deployed to a virtual machine which serves the web app to users. The OCA Composer app takes the user inputs and generates two types of files - the OCA File and the OCA Excel Template. Both of these files can be interpreted by parsers to generate the OCA Schema Bundle which is a single JSON file that contains the contents of the schema. Currently in this implementation only the OCA Excel Template is used and parsed to generate the OCA Schema Bundle. In the future, the OCA File will be directly consumed by an OCA Repository.
OCA Composer lets users upload a copy of a dataset which is stored in the users local environment, but OCA Composer only uses this to access the first row of the first sheet (if Excel) for attribute names. The data itself is not used further by OCA Composer and does not leave the users computer.
The JSON schema bundle can be consumed by several tools within the ADC/OCA ecosystem.
- OCA Readme consumes the JSON schema bundle and creates a human-readable plain text schema document.
- Data Entry Excel consumes the JSON schema bundle and creates an Excel sheet for data entry based on the information provided for in the schema.
You can clone the project using the git command-line interface or you can download the entire project as a zip using GitHub's user-interface. In the project directory, you can run:
Runs the app in the development mode.
Open http://localhost:3000 to view it in the browser.
The page will reload if you make edits to the code.
You will also see any errors/warnings in the console.
Builds the app for production to the build folder.
It correctly bundles React in production mode and optimizes the build for the best performance.
The build is minified and the filenames include the hashes.
Your app is ready to be deployed!
See the section about deployment for more information.
This code is created with support by Agri-food Data Canada, funded by CFREF through the Food from Thought grant held at the University of Guelph. Currently, we do not provide any warranty of any kind regarding the accuracy, security, completeness or reliability of this code or any of its parts.