Point-to-Point Calculator

For a limited time the Point-to-Point Calculator can be used at no cost. However, you must be logged into GeoCalc Online using an account tied to a Geographic Calculator order. If you have any issues with this process, please contact our Sales Team (orders@bluemarlbegeo.com)


The Point-to-Point Calculator has three different operations which can be performed: Convert, Forward, and Inverse.

Convert Operation

Enter a coordinate, select source and target systems , and select a transformation to convert the source point to the new coordinate system.

The source and target systems can be populated two ways:

  • From the search page, use the Action button and choose Set as Converter Source or Set as Converter Target to populate the Convert page.
  • On the convert page press the gray system button to navigate the systems by folders of type and region.

The point values will appear red when they have been edited manually and have not been calculated or recalculated.

The bar below the point converter will inform you of any messages.

How to set up the Convert Operation:

  1. Under Source Point Coordinate System, select the coordinate system that corresponds to the source point coordinate that is to be converted:
    • Click in the System field to bring up a selection dialog for the horizontal coordinate system. Expand and navigate through the menus on the left side to locate your source horizontal coordinate system on the right side of the dialog. Select the horizontal CRS on the right side of the dialog and click OK to populate the System, Datum, and Units fields.
    • Click on the Vertical field to bring up a selection dialog for the vertical coordinate system. Expand and navigate through the menus on the left side to locate and select the vertical coordinate system on the right side of the dialog. Click OK to populate the vertical field.
    • Use the Format option to the right of the Units field to specify the format of the coordinates.
  2. Under Source Coordinate Point Definition enter the name and coordinates for the source point.
  3. Select the target coordinate system (using the same steps as above) to convert the coordinate to, under Target Point Coordinate System.
  4. If necessary, select a transformation by clicking Select Transform below the transformation box in the center of the page.

    If you try to calculate and do not have a needed transformation selected, a red warning will inform you to select a transformation for your point conversion.
  5. Click Calculate to convert the point and populate the Target Coordinate Point Definition fields.


Forward Operation

A Forward calculation is used to compute a new coordinate that is a given distance and azimuth away from a starting coordinate. The conversion will be calculated using either Geodesic (Great Circle), Rhumb Line (Constant Azimuth), or CCG. To complete a Forward calculation, you must enter:

  • A target coordinate system (on the same Datum as the starting coordinate)
  • A starting coordinate and it's coordinate system
  • Distance and Azimuth ahead from the starting coordinate (or CCG string, in the case of the CCG method)

Setting up a Forward operation will be similar to the Covert operation, as described above, with one exception. You will specify method parameters rather than transformation parameters.


Inverse Operation

An Inverse calculation computes the distance between two known coordinates on the same datum. The result may be calculated using Geodesic, Rhumb, or CCG methods. Both the source and destination points must be referenced to the same geodetic datum.

This is also true for Geocentric coordinate systems that are 3 dimensional by nature. 3D Cartesian coordinates will be reduced to the surface of the datum.

Setting up a Inverse operation will require setting up Sours and Target Coordinate Point Definitions, along with Source and Target Point Coordinate systems. The Distance, Azimuth, and Bath Azimuth will be calculated from those parameters.