{"uid":"cap_b3TSvrt-oFP_629MAnN01","slug":"touchstone-earth-magnetic-field-api-0c689cd6","name":"Touchstone Earth Magnetic Field API","description":"Deterministic WMM2025 magnetic field (one location/date). Free sample, no payment required: GET /play/field","url":"https://touchstone.locomot.io/field","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET","HEAD","DELETE"],"type":"string"},"queryParams":{"type":"object","required":["lat","lon"],"properties":{"lat":{"type":"number","maximum":90,"minimum":-90},"lon":{"type":"number","maximum":180,"minimum":-180},"when":{"type":"string","description":"ISO date / decimal year; default now"},"altitude_km":{"type":"number","description":"optional, default 0; WMM valid [-1,850]"}}}},"additionalProperties":false},"output":{"type":"object","properties":{"model":{"type":"string"},"query":{"type":"object"},"units":{"type":"object"},"engine":{"type":"string"},"down_Z_nT":{"type":"number"},"east_Y_nT":{"type":"number"},"north_X_nT":{"type":"number"},"model_epoch":{"type":"number"},"valid_range":{"type":"array"},"compass_note":{"type":"string"},"deterministic":{"type":"boolean"},"declination_deg":{"type":"number"},"inclination_deg":{"type":"number"},"secular_variation":{"type":"object"},"total_intensity_nT":{"type":"number"},"horizontal_intensity_nT":{"type":"number"}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.002","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.002/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.002","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_cclixVpQdUNnsUmSNVs29","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.002","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns Earth's magnetic field components, declination, inclination, and total intensity for a given latitude/longitude using the World Magnetic Model (WMM)","exampleAgentPrompt":"What's the magnetic declination and total field intensity at latitude 40.7128, longitude -74.0060 right now, at ground level?","exampleUseCases":null,"resultDescription":"A JSON object containing the magnetic field vector components (north X, east Y, down Z in nanoteslas), declination in degrees, inclination in degrees, horizontal intensity, total intensity in nT, secular variation rates, the model name and epoch, valid date range, and a compass note explaining the declination offset.","failureModes":["Missing required lat or lon parameters returns a validation error","Latitude out of range [-90,90] or longitude out of range [-180,180] returns schema validation error","Altitude outside WMM valid range [-1, 850 km] may produce unreliable results","Invalid ISO date or decimal year in 'when' parameter returns a parse error","Payment not included or insufficient USDC results in HTTP 402 Payment Required"],"whenToPreferThis":"Use this endpoint when you need precise, model-based Earth magnetic field data — including declination for compass correction, inclination, field intensity, and secular variation — at any geographic coordinate on or near Earth's surface. Prefer this over generic geolocation APIs when the application involves navigation correction, magnetometer calibration, geophysical surveys, or any use case requiring WMM-standard magnetic field values.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-13T18:45:51.284Z","isFirstParty":false}