Coordinate Master



Three tools in one, this powerful app allows you to convert coordinates between many of the world's coordinate systems, compute the geoid offset, and estimate the current or historic magnetic field for any location. You can also view and/or enter the MGRS grid reference for a location.

The app uses the PROJ4 library and a lookup file containing projection and datum parameters to support over 1700 coordinate systems. Lat/lon, UTM, US State Plane, and many, many others are supported. You can also create your own coordinate systems if you know the parameters.The app also supports affine transformations to allow you to set up local grid systems. See for details.

The app either takes manual coordinate input or uses your current GPS location. The computed location can be displayed in Google Maps via your web browser with a single button press.

The magnetic field calculator page computes the Earth's current or historical magnetic field at a given location. The magnetic declination computed is useful for compass navigation since it represents the difference between true north and magnetic north. Field inclination and total intensity are also computed. This tool uses the International Geomagnetic Reference Field model (IGRF-12). See for full details. Years from 1900 through to 2020 are supported.

The app also includes buttons to compute the geoid height offset for the current position. These use the EGM96 model. Geoid offset can be subtracted from the height reported by GPS to give your actual height above sea level.

Online help for the app is available at

Permissions required: (1) GPS - to determine your location, (2) SD card access - to read and write user projections file.

Note 1: This app was previously called "World Coord Sys Tool". If you had this version installed and edited the user_projections.txt file, then you will need to copy this file to the CoordinateMaster folder on your device's SD card (or emulated SD card location).

Note 2: The convention used for the rx,ry, and rz values in the 7 parameter toWGS84 values may be different to some other software. If you experience a subtle difference in the results for a user projection which you create, try reversing the signs of these values.

Tags: world coordinate system tool proj4 , latitude longitude to easting northing , world coord sys tools , mollweide proj4 , equidistant conic projection agd84

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