Users also can type in a set of coordinates as well as azimuth and bearing and find coordinates of a new point or enter two points and get the distance. The heart of Geographic Calculator is the amount of conversions supported. The list is impressive. A massive list of datums also are present as well as six methods for horizontal datum conversion and three for vertical conversions. Blue Marble documentation reports that HARN information is available for six U.S. states.
Users also can provide their own ellipsoid parameters and create their own transfor-mations.
Most GIS users are content to perform horizontal transformations, but vertical values in coordinates also are effected by differences in datums. It's always possible to choose the wrong conversion option, but the folks at Blue Marble have made the process as painless as possible. The large number of conversion options may prove confusing. GEO Asia Pacific Copyright 2001 by Adams Business Media . All rights reserved.