1. Total intensity of the earth's magnetic field, epoch 1985.0 Author/Creator: United States. Defense Mapping Agency. Hydrographic/Topographic Center Publication/Creation: Washington, D.C. : The Center : [DMA, Combat Support Center, DOA, distributor], 1985 Format: Map Edition: 5th ed., Nov. 23, 1985 (Correct through NM 47/85). Access & Availability: Loading