How about 0 meters in wgs84 lat lon (what you get from most GPS) is sea level everywhere? More info for those that asked: http://www.esri.com/news/arcuser/0703

How about 0 meters in wgs84 lat lon (what you get from most GPS) is sea level everywhere? More info for those that asked: http://www.esri.com/news/arcuser/0703/geoid1of3.html http://www.esri.com/news/arcuser/0703/geoid1of3.html