Using CrowdMag to Catalog Magnetic Anomalies from Urban Infrastructure and Geological Features

5635091">NOAA's 5635091">CrowdMag5635091"> 5635091">app 5635091">is 5635091">developed for crowd-sourcing magnetic data5635091"> from 5635091">smartphones'5635091"> built-in magnetometer. 5635091">We 5635091">use 5635091">CrowdMag5635091"> app5635091"> for mapping magnetic anomalies from urban infrastructure 5635091">(iron pipes, 5635091">bridges etc.)5635091"> and5635091"> 5635091">a 5635091">geologic feature5635091"> (iron dike)5635091">. 5635091">Cataloging these local magnetic 5635091">anomalies5635091"> can5635091">, in theory,5635091"> help to improve 5635091">the 5635091">accuracy 5635091">of 5635091">magnetic5635091"> navigation systems. 5635091">We use a simple5635091"> forward modeling 5635091">approach5635091"> based on5635091"> spher5635091">ical (dipole) sources5635091"> 5635091">at different 5635091">positions, 5635091">depths and 5635091">magnetic intensity5635091"> in order to match 5635091">anomalies observed using5635091"> 5635091">CrowdMag5635091">. Our results show5635091"> that we can locate and map5635091"> significant magnetic 5635091">anomalies from urban infrastructure features5635091"> and we can use5635091"> 5635091">source 5635091">modeling5635091"> 5635091">to5635091"> identify the depths and strengths of each anomaly5635091">.5635091"> 5635091">F5635091">uture data collection can aid in alternative navigation and may 5635091">allow 5635091">use 5635091">of 5635091">these signatures as magnetic "mile markers."5635091"> 5635091"> 35551550":1,"335551620":1,"335559731":720}"">