HAPI: An API Standard for Accessing Heliophysics Time Series Data. Issue 12 (7th December 2021)

• Record Type: Journal Article
• Authors: Weigel, Robert S.; Vandegriff, Jon; Faden, Jeremy; King, Todd; Roberts, D Aaron; Harris, Bernard; Candey, Robert; Lal, Nand; Boardsen, Scott; Lindholm, Chris; Lindholm, Doug; Baltzer, Thomas; Brown, Lawrence E.; Grimes, Eric W.; Cecconi, Baptiste; Génot, Vincent; Renard, Benjamin; Masson, Arnaud; Martinez, Beatriz
• Is Part Of: Journal of geophysical research. Volume 126:Issue 12(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-12-07
• Subjects: API -- data -- time series; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2021JA029534
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: Heliophysics data analysis often involves combining diverse science measurements, many of them captured as time series. Although there are now only a few commonly used data file formats, the diversity in mechanisms for automated access to and aggregation of such data holdings can make analysis that requires intercomparison of data from multiple data providers difficult. The Heliophysics Application Programmer's Interface (HAPI) is a recently developed standard for accessing distributed time series data to increase interoperability. The HAPI specification is based on the common elements of existing data services, and it standardizes the two main parts of a data service: the request interface and the response data structures. The interface is based on the REpresentational State Transfer (REST) or RESTful architecture style, and the HAPI specification defines five required REST endpoints. Data are returned via a streaming format that hides file boundaries; the metadata is detailed enough for the content to be scientifically useful, e.g., plotted with appropriate axes layout, units, and labels. Multiple mature HAPI‐related open‐source projects offer server‐side implementation tools and client‐side libraries for reading HAPI data in multiple languages (IDL, Java, MATLAB, and Python). Multiple data providers in the US and Europe have added HAPI access alongside their existing interfaces. Based on this experience, data can be served via HAPI with little or no information loss compared to similar existing web interfaces. Finally, HAPI has been recommended as a COSPAR standard for time series data delivery. Plain Language Summary: The Heliophysics Application Programmer's Interface (HAPI) specification allows data providers to use a standard set of conventions for returning data in response to a URL‐based request. This specification was developed because no standard exists. Data providers use incompatible conventions so that automated access to and aggregation of data requires users to write custom code for each data provider. The benefit to the user is that software libraries for many common languages have been developed to read HAPI data; if a data provider serves data using the HAPI specification, the user does not need to write additional code to access the data. The starting point for using and learning more about HAPI is http://hapi-server.org/ . Key Points: HAPI was developed because there are many nonstandard approaches to serving Heliophysics time series data HAPI provides a standard specification that will simplify data access Software libraries for downloading data from HAPI servers in many commonly used programming languages are available