ERDDAP

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Revision as of 11:06, 19 January 2022 by Jpa029 (talk | contribs)

ERDDAP

https://erddap.bcdc.no/erddap

Here after you could find a quick overview of what is ERDDAP and how to use it.

what is ERDDAP

ERDDAP is a data server that give a simple, consistent way to download subsets of scientific datasets in common file formats (and make graphs and maps).

ERDDAP focus on making Easier Access to Scientific Data

why do we need it

Different scientific communities have developed different types of data servers (OPeNDAP, WCS, SOS, OBIS,...). It may be difficult to get data from those different types of servers:

  • Different data servers make your data request in different ways.
  • Different data servers return data in different formats, usually not the common file format that you want.
  • Different datasets use different formats for time data, so the results are hard to compare.

How ERDDAP helps to handle it

ERDDAP unifies the different types of data servers so you have a consistent way to get the data you want, in the format you want.

ERDDAP can get data from local and remote data sources via standardized requests

  • ERDDAP offers an easy-to-use, consistent way to request data: via the OPeNDAP standard.

ERDDAP acts as a middleman between you and various remote data servers. When you request data from ERDDAP, ERDDAP reformats the request into the format required by the remote server, sends the request to the remote server, gets the data, reformats the data into the format that you requested, and sends the data to you. You no longer have to go to different data servers to get data from different datasets.

Note: Many datasets can also be accessed via ERDDAP's Web Map Service (WMS).

ERDDAP gets the data, reformats the data into the format that you requested

  • ERDDAP can get data from local (on the server's hard drive) and remote (accessed via the web) data sources.
  • ERDDAP handles:
    • Grid datasets, data variables are multi-dimensional arrays of data.
    • Tabular datasets, data can be represented as a database-like table with rows and columns
  • ERDDAP returns data in the common file format of your choice:
    • ESRI .asc
    • ESRI .csv
    • OPeNDAP binary
    • .mat
    • Google Earth .kml
    • .nc
    • ODV .txt
    • .csv
    • .nccsv
    • .tsv
    • .json
    • .xhtml
  • ERDDAP can also return a .png or .pdf image with a customized graph or map.

ERDDAP standardizes the variable names and units for longitude, latitude, altitude, depth, and time in the results

The requests and results in ERDDAP use standardized space/time axis units:

  • longitude is always in degrees_east.
  • latitude is always in degrees_north.
  • altitude is always in meters with positive=up.
  • depth is always in meters with positive=down.
  • time, when formatted as a number, is always in "seconds since 1970-01-01T00:00:00Z"

ERDDAP can add and/or modify metadata

Many data sources have little or no metadata describing the data. ERDDAP lets the administrator describe metadata which will be added to datasets and their variables on-the-fly.

How to use ERDDAP

You can use ERDDAP for searching for datasets, for downloading data, for making maps through:

  • web pages (for humans with browsers).
  • RESTful web services (for computer programs).

How to use ERDDAP web pages

ERDDAP BCDC webpage

ERDDAP ICOS main.png

How to use ERDDAP RESTful services

You can bypass ERDDAP's web pages and use ERDDAP's RESTful web services directly from any computer program (for example, Matlab, R, or a program that you write) and even from web pages (via HTML image tags or JavaScript).

erddapy
Python language package for simplified access to ERDDAP servers.
erddap-python
Python library for the ERDDAP Restful API, that can obtain status metrics, provides search methods, and it gives tabledap and griddap class objects for metadata and data access.
rerddap
R language package for simplified access to data in any ERDDAP server, can also be installed from CRAN.
rerddapXtracto
R language package that uses rerdddap to extract data from ERDDAP servers along a trajectory or inside a polygon.
erddap-highstock-viewer
Simple pure JavaScript example to demonstrate display of long time series in HighCharts from a CORS enabled ERDDAP RESTful API.

See also

You could also find other tools to use on top of ERDDAP.‎
See the Awesome ERDDAP list of ERDDAP-related projects.