ERDDAP

The Problems that ERDDAP Tries To Solve

• You are looking for a specific type of oceanographic data (for example, satellite sea surface temperature data).
• Unfortunately, the datasets of interest are hard to find because they are at many different web sites.
• And each site requires a different protocol to request the data (for example, HTTP GET, XML, SOAP+XML, DAP, WCS, WFS, SOS, or an HTML form).
• And each site returns the data in a different format (for example, XML, SOAP+XML, DAP binary data stream, ASCII text, HDF 4, HDF 5, NetCDF, ...)
  and it isn't the common file format that you want (for example, .html table, ESRI .asc, Google Earth .kml, .mat, .nc, .csv, .tsv, .json, .xhtml).
• And data from different sites is hard to compare because the dates+times are expressed in different formats (for example, "Jan 2, 1985", "02-JAN-1985", "1/2/85", "2/1/85", "1985-01-02", or days since has Jan 1, 1980, or ...).

• ERDDAP is a web-based service that aggregates data from diverse remote sources and offers a simple, consistent way to access the data.
• ERDDAP offers different ways to search for datasets of interest (see options at right).
• ERDDAP lets you make requests in a standardized way, regardless of the data source's request protocol.
  • Gridded data is available via the DAP hyperslab protocol.
  • Tabular data is available via the DAP constraint protocol.
  ERDDAP also provides Data Access Forms (web pages) which help humans create the DAP requests.
  OPeNDAP's DAP is the recommended IOOS DMAC data transport mechanism and a NASA EOSDIS standard. (DAP is great!)
• ERDDAP lets you choose the file format for the results (for example, .html table, ESRI .asc, Google Earth .kml, .mat, .nc, .csv, .tsv, .json, .xhtml).
• ERDDAP standardizes the dates+times in the results, either as:
  • UDUNITS-compatible "seconds since 1970-01-01T00:00:00Z" numbers, or
  • ISO 8601 format strings (YYYY-MM-DDThh:mm:ssZ, for example, "1985-01-02T00:00:00Z").
  To avoid time zone and daylight savings confusion, time values are always converted to the UTC time zone.
• ERDDAP lets you request .png and .pdf image files with graphs and maps of the data, in addition to the raw data. Three special uses of these images are:
  • Web page authors can embed a graph with the latest data in a web page using an HTML <img> tag.
  • Anyone can use ERDDAP's Slide Sorter to build a personal web page that displays graphs with the latest data (or other images or HTML content), each in its own, draggable slide.
  • Anyone can use or make Google Gadgets to display images with the latest data on their iGoogle home page.
• ERDDAP has REST- and ROA-style links to make its services available to computer programs, so that other web services can be built on top of ERDDAP.
• More Detailed Information

Get Started with ERDDAP:
Search for Datasets of Interest

• View a List of All Datasets

• Do a Full Text Search for Datasets

  

• Search for Datasets by Category

  Datasets can be categorized in different ways by the values of various metadata attributes.
  Click on an attribute (institution, ioos_category, long_name, standard_name) to see a list of categories (values) for that attribute.
  Then, you can click on a category to see a list of relevant datasets.

• Search for Datasets by Protocol

  Protocols are the standards which define how to request data.
  Different protocols are appropriate for different types of data and for different client applications.
  Click on a protocol to see a list of datasets which are available via that protocol in ERDDAP.
   

  Protocol	Description
  griddap	griddap lets you use the DAP hyperslab protocol to request gridded data (for example, satellite data and climate model data) and graphs of gridded data.
  tabledap	tabledap lets you use the DAP constraint protocol to request tabular data (for example, buoy data) and graphs of tabular data.
  WMS	The Web Map Service (WMS) lets you request an image with data plotted on a map.