New Geographic Coordinate System
Feature Description
The Coordinate System Settings dialog box supports creating new geographic coordinate systems.
Feature Entry
- Image Panel->Dataset Context Menu->Properties->Coordinate System item in properties panel->Reset Coordinate System... Button->Coordinate SystemSettings Dialog->New Coordinate System Dropdown->Geographic Coordinate System Button.
- Map Context Menu->Properties->Coordinate System option in MapsProperties Panel->Reset Coordinate System... Button->Coordinate SystemSettings Dialog->New Coordinate System Dropdown->Geographic Coordinate System Button.
Steps
- Select Geographic Coordinate System from New Coordinate System dropdown in Coordinate System Settings dialog to open Custom Geographic Coordinate System dialog.
- Parameter descriptions in the dialog:
- Name: Specifies the name of custom geographic coordinate system.
- Datum: A datum defines the reference frame for Earth's surface measurements based on a spheroid model. Commonly used datums in China include Beijing1954, Xian1980, and China2000. Select from the dropdown, or choose <UserDefined> if predefined options are insufficient.
- Reference Spheroid: Mathematical models approximating Earth's shape. Common spheroids in China include Krasovsky1940 (Semimajor axis: 6,378,245.0m, Flattening: 1/298.3) and International1975 (Semimajor axis: 6,378,140m, Flattening: 1/298.257). Automatically populated based on selected datum, editable only when datum is <UserDefined>.
- Semimajor Axis: Auto-populated with spheroid selection. Editable when reference spheroid is <UserDefined>.
- Spheroid Flattening: Auto-populated with spheroid selection. Editable when reference spheroid is <UserDefined>.
- EPSG Code: Unique identifier in EPSG Geodetic Parameter Registry representing specific coordinate system configurations.
- Prime Meridian: Defines the origin longitude (0°). Typically Greenwich. Select from dropdown list of predefined meridians.
- Projection Height: Sets the height parameter for projection.
- Complete parameters to create geographic coordinate system.
Related Topics
New Projected Coordinate System
Create Coordinate System by EPSG Encoding