{"components":{"parameters":{"Altitude":{"description":"Geodetic Altitude above the reference ellipsoid in kilometers. Range 0 to 600 km.","in":"query","name":"altitude","required":true,"schema":{"example":10,"maximum":1000,"minimum":0,"type":"number"}},"Day":{"description":"Calendar day of month. Must be valid for the given month/year.","in":"query","name":"day","required":true,"schema":{"example":1,"maximum":31,"minimum":1,"type":"integer"}},"Latitude":{"description":"Geodetic latitude in degrees. Range -90 (S) to 90 (N).","in":"query","name":"latitude","required":true,"schema":{"example":80,"maximum":90,"minimum":-90,"type":"number"}},"Longitude":{"description":"Geodetic longitude in degrees. Range -180 (W) to 180 (E).","in":"query","name":"longitude","required":true,"schema":{"example":100,"maximum":180,"minimum":-180,"type":"number"}},"Month":{"description":"Calendar month (1-12).","in":"query","name":"month","required":true,"schema":{"example":7,"maximum":12,"minimum":1,"type":"integer"}},"Year":{"description":"Calendar year (integer). Range depends on the deployed coefficients/model epoch.","in":"query","name":"year","required":true,"schema":{"example":2027,"maximum":2030,"minimum":2025,"type":"integer"}}},"schemas":{"Error":{"properties":{"details":{"additionalProperties":true,"type":"object"},"error":{"type":"string"}},"required":["error"],"type":"object"},"GeoMagneticElements":{"properties":{"X":{"description":"North component of magnetic field.","properties":{"units":{"type":"string"},"value":{"type":"number"}},"type":"object"},"Y":{"description":"East component of magnetic field.","properties":{"units":{"type":"string"},"value":{"type":"number"}},"type":"object"},"Z":{"description":"Down component of magnetic field.","properties":{"units":{"type":"string"},"value":{"type":"number"}},"type":"object"},"declination":{"description":"Declination angle, magnetic north relative to true north.","properties":{"units":{"type":"string"},"value":{"type":"number"}},"type":"object"},"grid_variation":{"description":"Grid variation. Only defined for high latitudes in polar stereographic context; may be null/NaN when not defined (implementation-dependent).\n","nullable":true,"properties":{"units":{"type":"string"},"value":{"type":"number"}},"type":"object"},"inclination":{"description":"Inclination / dip angle.","properties":{"units":{"type":"string"},"value":{"type":"number"}},"type":"object"}},"required":["X","Y","Z","inclination","declination","grid_variation"],"type":"object"}}},"info":{"description":"Geomagnetism refers to the magnetic field produced by the Earth, known as the geomagnetic field. This API calculates World Magnetic Model (WMM) High Resolution predictions for a given geodetic position (latitude/longitude/altitude) and date (year/month/day).\n<br> <ul> <li>Higher spatial resolution than WMM2025: ~300 km at the equator vs ~3330 km for WMM2025 (approx 10x finer).</li> <li>Extended spherical harmonics: degrees 1-15 (core + secular variation) plus explicit crustal field degrees 16-133.</li> <li>Orders of magnitude more coefficients: ~18,210 non-zero coefficients vs 336, improving regional fidelity.</li> <li>Reduced omission error in crustal field, with materially better performance over continents and tectonically complex regions.</li> </ul>\n<br> API requests must contain a key \"API-Key\" in the header (see code samples). <br><br> Visit our <Button to='#' transparent><a href='https://developer.amentum.io'>Developer Portal</a></Button> to obtain a key with a 14 day free trial.<br><br> Amentum Pty Ltd is not responsible nor liable for any loss or damage of any sort incurred as a result of using the API. <br><br> NOTE: accuracy may be degraded during space weather events / geomagnetic storms. Copyright <a href='https://amentum.space'>Amentum Pty Ltd</a> 2026.\n","title":"Geomag API","version":"3.0.0","x-logo":{"altText":"Amentum Aerospace","backgroundColor":"#FFFFFF","url":"https://amentum.io/static/img/AMENTUMSPACE_GREY_SMALL.jpg"}},"openapi":"3.0.0","paths":{"/wmmhr":{"get":{"description":"Returns the full set of geomagnetic elements for geodetic latitude/longitude (deg), geodetic Altitude (km), and calendar date.\n","operationId":"app.api_models.endpoints.WMMHR.magnetic_field","parameters":[{"$ref":"#/components/parameters/Latitude"},{"$ref":"#/components/parameters/Longitude"},{"$ref":"#/components/parameters/Altitude"},{"$ref":"#/components/parameters/Year"},{"$ref":"#/components/parameters/Month"},{"$ref":"#/components/parameters/Day"}],"responses":{"200":{"content":{"application/json":{"example":{"X":{"units":"nT","value":10420.5},"Y":{"units":"nT","value":7065.2},"Z":{"units":"nT","value":56912.3},"declination":{"units":"Deg","value":34.1441},"grid_variation":{"units":"Deg","value":-65.8559},"inclination":{"units":"Deg","value":87.9826}},"schema":{"$ref":"#/components/schemas/GeoMagneticElements"}}},"description":"Successful WMMHR calculation"},"400":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/Error"}}},"description":"Invalid parameters (out of range / malformed)"},"401":{"content":{"application/json":{"schema":{"$ref":"#/components/schemas/Error"}}},"description":"Missing/invalid API key"}},"summary":"Calculate WMMHR geomagnetic elements of declination, inclination, grid variation and mag field vector components","tags":["wmmhr"],"x-codeSamples":[{"lang":"Shell","source":"curl -X GET \"https://geomag.amentum.io/wmmhr?altitude=10&latitude=80&longitude=100&year=2027&month=7&day=1\" \\\n  -H \"accept: application/json\" \\\n  -H \"API-Key: <your_key>\"\n"}]}}},"servers":[{"url":""}],"tags":[{"description":"The World Magnetic Model High Resolution calculates geomagnetic field vector components and derived elements at a specific date, geodetic altitude, latitude, and longitude. A description of the WMMHR, including its features and limitations, can be found <a href='https://www.ncei.noaa.gov/products/world-magnetic-model-high-resolution'>here</a>. <br><br> Visit our <Button to='#' transparent><a href='https://developer.amentum.io'>Developer Portal</a></Button> to obtain an API key with a 14 day free trial.\n","name":"wmmhr","x-displayName":"World Magnetic Model High Resolution (WMMHR)"}]}