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HAPI: An API Standard for Accessing Heliophysics Time Series Data
  • +16
  • Robert S Weigel,
  • Jon Vandegriff,
  • Jeremy B. Faden,
  • Todd King,
  • D Aaron Roberts,
  • Bernard Harris,
  • Robert M. Candey,
  • Scott A. Boardsen,
  • Doug Lindholm,
  • Chris Lindholm,
  • Thomas Baltzer,
  • Lawrence Elwin Brown,
  • E. W. Grimes,
  • Baptiste Cecconi,
  • Vincent Génot,
  • Arnaud Masson,
  • Beatriz Martinez,
  • Benjamin Renard,
  • Nand Lal
Robert S Weigel
George Mason University, George Mason University

Corresponding Author:[email protected]

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Jon Vandegriff
Johns Hopkins University, Johns Hopkins University
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Jeremy B. Faden
University of Iowa, University of Iowa
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Todd King
University of California Los Angeles, University of California Los Angeles
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D Aaron Roberts
NASA GSFC, NASA GSFC
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Bernard Harris
NASA/GSFC, NASA/GSFC
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Robert M. Candey
NASA Goddard Space Flight Center, NASA Goddard Space Flight Center
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Scott A. Boardsen
NASA/GSFC-GPHI, NASA/GSFC-GPHI
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Doug Lindholm
University of Colorado/LASP, University of Colorado/LASP
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Chris Lindholm
University of Colorado/LASP, University of Colorado/LASP
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Thomas Baltzer
University of Colorado/LASP, University of Colorado/LASP
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Lawrence Elwin Brown
The Johns Hopkins University Applied Physics Laboratory, The Johns Hopkins University Applied Physics Laboratory
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E. W. Grimes
University of California Los Angeles, University of California Los Angeles
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Baptiste Cecconi
Observatoire de Paris, Observatoire de Paris
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Vincent Génot
IRAP, IRAP
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Arnaud Masson
European Space Agency, European Space Agency
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Beatriz Martinez
RHEA Group for ESA, RHEA Group for ESA
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Benjamin Renard
AKKA Technologies, AKKA Technologies
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Nand Lal
NASA GSFC, NASA GSFC
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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 inter-comparison 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.
Dec 2021Published in Journal of Geophysical Research: Space Physics volume 126 issue 12. 10.1029/2021JA029534