EarthRef.org Digital Archive (ERDA) -- GeoForshungsZentrum magnetic anomaly candidate map

Description
The World Digital Magnetic Anomaly Map (WDMAM) is an ongoing effort towards the mapping of worldwide available aeromagnetic data. It is led by a task force of the International Association for Geomagnetism and Aeronomy (IAGA) and aims at distributing a global map in printed and digital forms. The official release will be done by the WDMAM commitee and will be available at www.ccgm.org. The candidate grid presented here is a work from the team of the GeoForshungsZentrum of Potsdam (Germany).

Instructions
#Administrative definition
Contact address: GeoForschungsZentrum, Telegrafenberg, 14473 Potsdam, Germany
Contact Persons : mioara@gfz-potsdam.de ; lesur@gfz-potsdam.de

#Technical definition
Filename: GAMMA_v1.1.xyzi.gz
Quantities given: Lon, Lat, dFa (all wavelengths), index
Altitude: constant above mean terrain; alt = 5000 m
Format: 3 decimal digits
Coordinate system: lat, lon; WGS84
Spatial grid resolution: 3? (0.05degree grid)

#Other specification
Longitudes between -179.95 and 180 inclusive and latitudes between 89.95 and -89.95 inclusive (poles missing).