Create New Coordinate System

Introduction

“Coordinate System Settings” dialog box supports create a new coordinate system.

Basic Steps

1. In the “Coordinate System Settings” dialog box, click the “Create New Coordinate System” drop-down button and select “Geographic Coordinate System” to bring up the “Custom Geographic Coordinate System” dialog box.

2. In Custom Geograpgic Coordinate System dialog box, the following parameters need to be set:

   • Name: Set the custom geographic coordinate system name.

   • Datum is established based on the of the earth ellipsoid, which defines the position of the Earth’s ellipsoid relative to the Earth’s sphere, providing a reference frame for the measurement of surface features, determining the origin and direction of the surface latitude and longitude network, In short, is the positioning and orientation of the ellipsoid. Each country or region has its own datum, and China’s two commonly used datum include: Beijing 54 coordinate system (Beijing1954), Xi’an 80 coordinate system (Xian1980).

     • System Predefined Datum: Click the drop-down button on the right to pop up a list of datum that you can select from a drop-down list of a system-defined datum type. If you choose the ground reference plane provided by the system, reference ellipsoid and ellipse long axis / flat and other parameters are fixed can not be edited.
     • Custom Datum: The user can enter a new name in the text box to the right of the label as the name of the custom datum. You can customize the reference ellipsoid and ellipse long axis / flat and other related parameters.

   • Reference Ellipsoid: The surface of the earth’s ellipsoid is a regular mathematical surface expressed by a data formula. The surface of the earth’s ellipsoid is commonly used in the measurement and mapping to replace the natural surface of the earth. “Ellipsoid parameters” in the application should choose the appropriate Earth ellipsoid based on the specific circumstances of each country or region. Commonly used ellipsoids in our country include: Krasovsky1940 (equatorial radius 6378245.0 m, flat rate 1 / 298.3), International1975 (equatorial radius 6378140, flattened 1 / 298.257) and so on.

     • System Predefined Reference Ellipsoid: Click the drop-down button on the right to bring up the reference ellipsoid list. You can select a system pre-defined reference ellipsoid type in the drop-down list.
     • Custom Reference Ellipsoid: The user can enter a new name in the text box to the right of the label as the name of the custom reference ellipsoid. You can customize the reference ellipsoid and ellipse long axis / flat and other related parameters.
   • Prime Meridian: Prime Meridian Defines the starting position of the abscissa of the coordinate system. In most coordinate systems, the prime meridian is the meridian via Greenwich, London, England. Click the drop-down button on the right to pop up the list of prime meridians. You can select a system predefined prime meridian type in the drop-down list.
3. Complete the above parameters set, click “OK” button to complete creating new coordinate system.