The magnetometer satellite (Magsat) data are separated into two distinct sets: the dawn and the dusk sets. The two sets are analyzed independently because of the dawn-dusk asymmetry of the external magnetic field components of the data. Two scalar magnetic anomaly maps, the dawn and the dusk maps, are derived using the spherical harmonic expressions of the respective data set. The significant correlation of the two maps in the harmonic range of 18--41 indicates the repeatability of the Magsat data in these harmonics. The shortest repeatable wavelength is about 920 km. A band-limited global scalar magnetic anomaly map is derived at about 410 km altitude by arithmetic averaging of the dawn and the dusk maps. The map is then downward continued to about 10 km altitude. The downward continued magnetic anomalies are relatively more localized. The main features of the anomalies are as follows: (1) Continents have relatively stronger magnetic anomalies than oceans, especially the younger oceans, (2) many circum-Pacific subduction zones have magnetic signatures, and (3) there is no overall correlation between anomalies and major shields.