The Internet of Things and location-based services rely heavily on indoor pedestrian navigation. It is important yet costly to create a map for indoor navigation. Recent studies examine the creation of radio maps using crowdsourcing (such as WiFi and BLE). In situations when there are insufficient WiFi or BLE nodes, the magnetic field map is the sole way to deliver indoor locating services without infrastructure. Previous research on magnetic map construction using crowdsourcing do not fulfill the requirements of the real scenario. In this work, we provide a summary of the real-world requirements for the crowdsourcing- based magnetic map-building method. Furthermore, we proposed an efficient crowdsourcing-based magnetic map creation approach that is resilient to the proposed requirements: short- period trajectories, uncalibrated magnetometer sensors, different pedestrian motion patterns, and irregular trajectory shapes. In the field test, the proposed method consumed 60.8 seconds to generate a map from a 12-hour dataset that met the proposed requirements. When the duration of each trajectory is 90 seconds, the mean position error is 1.48m (with scale correction) and 2.53m (without scale correction).
