【實用工具app】World Coord Sys Tool|最夯免費app-gigacircle

This powerful app allows you to convert coordinates between many of the world's coordinate systems. It 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, including local grid systems.

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.

Supported projections:

* Albers Equal Area

* Azimuthal Equidistant

* Cassini

* Equal Area Cylindrical

* Eckert IV

* Eckert VI

* Equidistant Cylindrical

* Equidistant Conic

* Gall

* Lambert Conformal Conic

* Mercator

* Miller Cylindrical

* Mollweide

* Oblique Mercator

* Oblique Stereographic

* Polyconic

* Robinson

* Transverse Mercator

In addition to these projections, the app also supports affine transformations to allow you to set up local grid systems. See http://www.binaryearth.net/Miscellaneous/affine.html for details.

Online help for the app is available at http://www.binaryearth.net/WorldCoordSysToolHelp

The app also includes an IGRF calculator tool which used to be a separate app.

The IGRF calculator computes the Earth's current or historical magnetic field at a given location using the IGRF model. 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 which are useful for geophysics purposes. The input latitude and longitude are in decimal degrees and follow the usual conventions of -ve latitude being south and -ve longitude being west. This tool uses the International Geomagnetic Reference Field model (IGRF-12). See http://www.ngdc.noaa.gov/IAGA/vmod/igrf.html for full details. Years from 1900 through to 2020 are supported.

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

Note 1: If editing the user projections file from within the app, make sure to close the app and re-select the coordinate system you've changed otherwise your changes will not be refreshed in the app.

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.