erddap4js

erddap4js - ERDDAP JavaScript interface for the browser & Node

Simple ERDDAP library for JS, written in TypeScript. Works in Node or the browser. Supports tabledap and griddap queries. Browser version is dependency free.

Quickstart

Browser example

See a demo in demo/browser/index.html

Copy the file dist/browser/ERDDAP.js to the same folder with your HTML file.

<script src="ERDDAP.js"></script>
<script>
  document.addEventListener("DOMContentLoaded", async function () {
    const erddapServer = new ERDDAP("https://coastwatch.pfeg.noaa.gov/erddap");
 
    const tableData = await erddapServer.tabledap({
      dataset: "erdCinpKfmSFNH",
      variables: ["id", "common_name"],
      constraints: [
        ["time", ">=", "2007-06-24T00:00:00Z"],
        ["size", ">=", 140],
        ["common_name", "=~", ".*urchin.*"],
      ],
      distinct: true,
    });
  });
</script> 

Node example

The import is different, the rest is the same as the browser example above.

npm install erddap4js

const ERDDAP = require("erddap4js").default;

See a demo in demo/node/query.js

Documentation

• ERDDAP()
• tabledap()
• griddap()
• info()
• allDatasets()

ERDDAP()

const erddapServer = new ERDDAP("https://coastwatch.pfeg.noaa.gov/erddap");

To use debug mode add a second argument of true, this will console log URLs of all queries.

tabledap()

• Everything is case sensitive
• Constraints are ANDed together
• Operators are !=, =~, <=, >=, =, <, >
• Order types are: orderBy, orderByClosest, orderByCount, orderByLimit, orderByMax, orderByMin, orderByMinMax, orderByMean

await erddapServer.tabledap({
  dataset: "erdCinpKfmSFNH",
  variables: ["id", "common_name"],
  constraints: [
    ["time", ">=", "2007-06-24T00:00:00Z"],
    ["common_name", "=~", ".*urchin.*"],
  ],
  orderType: "orderBy", // optional
  orderVariables: ["common_name"], // must have unless it's "orderByCount"
  distinct: true, // optional
});

Sample response:

[{ id: "Anacapa (Landing Cove)", common_name: "Red sea urchin" } ... ];

griddap()

• Constraints are set differently for griddap.
• make sure to match number of dimensions with that of the dataset
• dimension properties must be ordered as they appear in the dataset (time, altitude, latitude, longitude)
• to add a stride argument (to get every nth value), add another element to the range array, eg ["2010-12-16T12:00:00Z", "2010-12-16T12:00:00Z",3]

await erddapServer.griddap({
  dataset: "jplAmsreSstMon_LonPM180",
  time: ["2010-12-16T12:00:00Z", "2010-12-16T12:00:00Z"],
  latitude: [50, 50],
  longitude: [-150, -120],
  variables: ["tos", "tosNobs", "tosStderr"],
});

Sample response:

[ { time: '2010-12-16T12:00:00Z',
  latitude: 50.5,
  longitude: -150,
  tos: 6.109735,
  tosNobs: 3175,
  tosStderr: 0.6101171 }, ... ]

info()

Get variable and global attribute information for this dataset

await erddapServer.info("erdCinpKfmSFNH");

Sample response:

[ { "Row Type": "attribute",
    "Variable Name": "NC_GLOBAL",
    "Attribute Name": "acknowledgement",
    "Data Type": "String",
    "Value": "NOAA NESDIS COASTWATCH, NOAA SWFSC ERD, Channel Islands National Park, National Park Service"
    },
    ...
  { "Row Type": "variable",
    "Variable Name": "longitude",
    "Attribute Name": "",
    "Data Type": "double",
    "Value": "",
  }, ...]

allDatasets()

Get metadata for all datasets- griddap, tabledap and others

await erddapServer.allDatasets();

Sample response:

[
  {
    datasetID: 'jplAmsreSstMon',
    accessible: 'public',
    institution: 'Remote Sensing Systems',
    dataStructure: 'grid',
    cdm_data_type: 'Grid',
    class: 'EDDGridSideBySide',
    title: 'AMSRE Model Output, obs4MIPs NASA-JPL, Global, 1 Degree, 2002-2010, Monthly',
      ... many more fields ...
  }, ... ]

CORS

Lots of ERDDAP servers won't support CORS, so you may run into this issue while trying to use ERDDAP in your browser. Read more about CORS and ERDDAP

Development

• npm run build - build the 'dist' directory
• npm test to run tests
• npm run coverage - to build a folder 'coverage' to see coverage reports in your browser
• act - test Github Actions with act