Get magnetic declination for given time and place. It's an adaptation of the World Magnetic Model by the NOAA National Geophysical Data Center.

$ npm install geomagnetism --save

var geomagnetism = require('geomagnetism');

// information for "right now"
var info = geomagnetism.model().point([44.53461, -109.05572]);
console.log('declination:', info.decl);

// use a specific date
var model = geomagnetism.model(new Date('12/25/2017'));
var info = model.point([44.53461, -109.05572]);
console.log('declination:', info.decl);

Copyright © 2015–2018 Natural Atlas, Inc. & Contributors

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.