Introduction

The Blue Marble Geographic Calculator™ product has become the leading coordinate conversion and geodetic calculation tool for Windows - worldwide. The foundational technology behind the Geographic Calculator is now available as a GeoDevelopment Component™ for developers who require embedded coordinate conversion and geodetic calculation support.

GeoCalc/DLL is a coordinate transformation "engine" that converts data from one coordinate system to another, as well as performing geodetic calculations. Used within any GPS, surveying, engineering, or mapping system, GeoCalc/DLL provides accurate geographic coordinate transformations and geodetic calculations. GeoCalc/DLL adopts a high-level parametric database model for the efficient storage and retrieval of coordinate system, map projection, ellipsoid, geodetic datum transformation, and unit parameters. GeoCalc/DLL can convert coordinates between Geodetic (Latitude and Longitude), Universal Transverse Mercator (UTM), US State Plane 1927 and 1983, Earth-centered Earth-fixed (ECEF), as well as many other coordinate systems and custom coordinate systems that you can easily define. Standard horizontal datum transformation methods are implemented including the Molodensky, DMA Multiple Regression Equation, Seven Parameter Bursa/Wolfe, NGS NADCON (NAD 27 to NAD 83), NGS High Accuracy Reference Network (HARN - NAD83 to enhanced NAD 83), and Canadian National Transformation (NAD 27 to NAD 83 within Canada) methods.

An application communicates with GeoCalc/DLL via a Dynamic Link Library (DLL) interface. Many development tools for Microsoft Windows can make use of GeoCalc/DLL, including C, C++, Visual C++, Borland C++, Symantec C++, Watcom C++, Microsoft Fortran, Borland Turbo Pascal, SQL Windows, Visual Basic, Borland Delphi and others.

GeoCalc/DLL uses a database to support pre-defined and user-defined geodetic objects, such as coordinate systems, datums, and ellipsoids. By doing so, GeoCalc/DLL supports an infinite amount of coordinate systems, datums, and ellipsoids. By using an ASCII representation, GeoCalcDLL's coordinate conversion database is both open and portable.