GeoCalculator

Delivered inside a lightweight package, GeoCalculator is mainly dedicated to programmers, including a DLL component that can be integrated within any GIS application in order to calculate some important parameters.
Aside from the library, the package also bundles a test application that demonstrates how the component actually works in practice. As such, you are prompted to enter the desired input values by filling in the designated fields.
When pressing the Calculate button, all the output data is displayed within the same window. GeoCalculator can quickly determine different geo variables, such as the distance between two points (using the cosinus theorem, Gaversinus for very large distances or Vincents inverse formulae), the initial bearing between two latitude or longitude points (by applying the Vincent or Vincent reverse theory) or the Gauss-Kruger coordinates.
In addition to this, it can be used to determine ellipsoid parameters (such as WGS84, SK42, SK95, PZ90 or Bessel 1941 Europe), as well as spatial coordinates.
The test application also comes with options to calculate the coordinates of a point based on the initial azimuth, the distance and other input values. Just like in the previous case, you are required to enter the desired values and press the Calculate button to generate the result (latitutde, longitude and reverse azimuth).
GeoCalculator is a handy component for those who intend on creating a GIS application. It can determine various variables and perform geodethic calculations (Pulkovo-42->WGS84, Pulkovo-95->Pulkovo-42, Pulkovo-42->Pulkovo-95 and WGS84->Pulkovo-42) in no time.