For your convenience, the GeoCalc Class Library supplies the UTM (Universal Transverse Mercator) grid, State Plane Coordinate System of 1927, State Plane Coordinate System of 1983, and many other coordinate system definitions. Furthermore, GeoCalc allows you to define any other coordinate systems you may wish to use. With GeoCalc, developers and users can use a wide range of projections and datums to define a custom system. Over 75 projection methods are contained in this software, and examples of equal-area, azimuthal, cylindrical, polyconic, and stereographic definitions are also available.
The GeoCalc Class Library includes read and write functions for the storage and retrieval of geodetic objects within an XML database. Geodetic objects including ellipsoids, datums, units, and coordinate systems are created and maintained in this database. For your convenience, Blue Marble Geographics supplies a comprehensive master geodetic database that you may ship with your application.
The GeoCalc Class Library supplies many datum and datum shift definitions for your use. Additionally, GeoCalc allows you to define custom datums and datum shifts not included with this library. For a list of the datum shift methods supported by GeoCalc, please consult the DatumShift ClassType enumeration.
GeoCalc comes with several ready-to-use dialogs that allow users to view, edit, add, remove, and select object definitions within the data source. These include the DataBrowser, DataSourceEditor, DataSourcePicker, DatumShiftPicker, ObjectEditor, and ObjectPicker dialogs.
The GeoCalc Class Library now allows users to shift directly between two datums (if the shift exists) without the use of WGS84 as an intermediary. The GeoCalc Class Library also allows the user of an intermediate datum for situations where this it's appropriate.
The GeoCalc Class Library supplies many ellipsoid definitions for your use, including WGS84, GRS 80, Clarke 1866, Clarke 1880, Krassovsky. GeoCalc also allows you to define your own ellipsoids.
The GeoCalc Class Library supports EPSG 6.14 codes allowing for easy selection of coordinate systems using codes from an industry standard.
The GeoCalc Class Library allows you to import coordinate systems from PRJ (ESRI ArcView), WKT (Well-Known Text), MAP (MapInfo), and TAB (MapInfo) files, and also export the coordinate systems to WKT. This allows you to easily add the coordinate system definitions to the data source currently loaded in memory, and then also save the definition back to a file.
In accord with the most common programming practices, the GeoCalc Class Library is a fully object-oriented cross-platform library. This design makes development fast and flexible by allowing GeoCalc users access to all the features of the original GeoCalc DLL, along with the freedom to create and reference unique objects that extend the features of GeoCalc for your specific needs.
Blue Marble Geographics ships the GeoCalc Class Library pre-loaded with coordinate conversion routines pertaining to most major projections. For a list of all of the projection types GeoCalc supports, please consult the Projection ClassType enumeration.
The NGS VERTCON method computes the difference in orthometric height between the NGVD29 and NAVD88 vertical datums for a specific latitude and longitude within the conterminous United States of America. VERTCON implements predetermined grid shifts (analogous to NADCON horizontal grid shift files) for any particular point on the grid. The VERTCON model is accurate to 2cm (assuming that data collection methods are at least that accurate or better). Since most of the data used to calculate the model fall in the eastern United States, accuracies in that part of the country will tend to be better than elsewhere.
GeoCalc provides users the ability to transform height data between several different height models and vertical datums. For a list of GeoCalc's supported height models, see the HeightModel ClassType enumeration.
GeoCalc now allows users to import coordinate system definitions given in the Geography Markup Language (GML) version 3.x into the data source. Once imported, these coordinate systems can be used like any other coordinate system, and they can be saved to the data source for use in future sessions.