The total number of degree confluences is 64,442, of which 21,543 are on land, 38,409 on water, and 4,490 on the Antarctic and Arctic ice caps. The project categorizes degree confluences as either "primary" or "secondary". A confluence is primary only if it is on land or within sight of land. In addition, at latitudes greater than 48o only some points are designated primary because confluences crowd together near the poles. Both primary and secondary confluences may be visited and recorded.