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Main Window

The main window consists of the following elements, from top to bottom:

- the Title Bar, which includes the standard Java window controls,
- the Menu Bar, which contains the following pull-down menus: File, Edit, Options, Datum, Ellipsoid, Convert, and Help,
- the upper area, which contains the following sub-elements:

- a Datum pull-down list, which displays the code and name of the currently selected datum, and which you can use to select a different datum,

- an Ellipsoid field, which displays the code and name of the reference ellipsoid associated with the currently selected datum,

- a pull-down list that displays the name of the currently selected coordinate reference frame, and which you can use to select a different coordinate reference frame,

- a set of zero or more parameter fields and/or controls for the currently selected coordinate reference frame,

- a set of coordinate fields and/or controls for the currently selected coordinate reference frame, which you can use to specify coordinate values that are to be converted,

– the standard error fields, in which input coordinate accuracy values can be entered, and which display output coordinate accuracy values for the most recent conversion. There are three fields. The 90% circular error (CE), in meters, estimates the horizontal accuracy of the output coordinates. The 90% linear error (LE), in meters, estimates the vertical accuracy of geodetic heights. The 90% spherical error (SE), in meters, estimates the three-dimensional accuracy of geocentric and local Cartesian coordinates.

– the Source pull-down menu, which displays the names of possible sources for input coordinates. These include GPS coordinates, various types of hardcopy maps, and various types of digital geospatial data. Selecting one of these entries causes all three of the standard error fields to be set to values appropriate for the selected source.

- the two Convert buttons, Convert (Upper-to-Lower) and Convert (Lower-to-Upper), which, when clicked, causes the coordinates specified in one area (upper or lower) to be converted to the datum and coordinate reference frame specified in the other area (lower or upper), and causes the resulting coordinate values to be displayed in the coordinate fields of the other area. The Convert buttons are color-coded as follows:

- Red indicates that one of the selected coordinate reference frames is incompatible with the corresponding datum selection, and therefore any attempted conversion operation will result in an error. Typically, this occurs when one of the currently selected coordinate reference frames (e.g., British National Grid) is only compatible with datums that use a specific ellipsoid (e.g., Airy).

- Yellow indicates that the valid regions for the two selected datums are disjoint from one another, and therefore any attempted conversion operation will result in a warning. Typically, this occurs when two local datums for different parts of the world (e.g., Europe and North America) are selected.

- Green indicates that the current coordinate reference frame and datum selections are compatible with one another.

- the lower area, which contains the same types of sub-elements as the upper area.

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