Map Projection - A Lambert Conformal Conic projection (with two standard parallels) is used for the ArcticNet Basemap series of mapsheets. In order to minimize distortion in the areas of most interest, the standard parallels were specifically chosen to follow the two major east-west channels through the Northwest Passage (Parry Channel and Queen Maud/Coronation Gulf). The projection parameters are as follows:
¿ 1st Standard parallel: 70°
¿ 2nd Standard parallel: 73°
¿ Origin latitude: 70°
¿ Origin longitude: -105°
¿ False easting: 2,000,000 metres
¿ False northing: 2,000,000 metres
Datums - Horizontal datum: NAD83; Vertical datum: soundings are reduced to mean sea level (MSL) using the WebTide tidal prediction models.
Misc. Processing Details
Since time is at a premium while underway, there are often cases where long transits are undertaken with little or no sound speed profiles collected. On the other hand, some oceanographic sections sampled by the Amundsen provide very dense sound speed information throughout the watercolumn. In sections where the watercolumn is poorly sampled, the 1/4 ° World Ocean Atlas (2001) climatology is used as a source of sound speed.
