Define Coordinate System

Click the New Geographic System or Modify buttons in the Assign Coordinate System dialog to open the Define Coordinate System dialog. The Define Coordinate System dialog allows you to create a Custom coordinate system. Select a Projection, enter the projection Parameters, and specify a Datum. Click OK and the new coordinate system will be added to the Assign Coordinate System dialog Custom list for future use.

 

Define a custom coordinate system in theDefine Coordinate Systemdialog.

 

Name

Specify a custom name for the new coordinate system in the Name box. When editing a predefined coordinate system, the name is automatically appended with (edited) after the existing name.

 

Projection

Select a projection from the Projection list. Specify custom Parameter and Value options. Unprojected Lat/Long does not have Parameter and Value options to specify.

 

The projection options include: Unprojected Lat/Long, Albers Equal Area Conic, Azimuthal Equidistant, Bonne, Cassini, Eckert IV, Eckert VI, Equidistant Conic, Equidistant Cylindrical, Gnomonic, Hotine Oblique Mercator, Lambert Azimuthal Equal Area, Lambert Conformal Conic, Mercator, Miller Cylindrical, Mollweide, Oblique Mercator, Orthographic, Polyconic, Robinson, Robinson-Sterling, Sinusoidal, Stereographic, Transverse Mercator, Universal Transverse Mercator (UTM), and Van Der Grinten.

 

Datum

Select a datum from the Datum list. Specify custom Parameter and Value options to fit your needs.

 

OK or Cancel

ClickOKto create your new custom coordinate system. The coordinate system will be listed in theCustomsection of the Assign Coordinate System dialog for this file.  If you want to save the custom coordinate system for future use, add the custom coordinate system to theFavoritessection. ClickCancelto return to the Assign Coordinate System dialog without creating a custom coordinate system.

 

Example 1: Defining a Custom Coordinate System

  1. In the Assign Coordinate System dialog, click the New Geographic System button to open the Define Coordinate System dialog.

  2. Change the Name to Lambert Conformal Conic Custom.

  3. From the Projection list, select Lambert Conformal Conic.

  4. Make any necessary changes to the Parameter or Values.

  5. Make any necessary changes to the Datumsection.

  6. Click OK and the Lambert Conformal Conic Custom projection is added to the Custom section.

  7. In the Assign Coordinate System dialog, select the custom projection and click OK.

 

Example 2: Saving a Custom Coordinate System

  1. In the Assign Coordinate System dialog, click the button to the left of Custom.

  2. Select the coordinate system in the Custom section and click theAdd to Favoritesbutton.

  3. Click the button to the left of Favorites to open the Favorites section. The custom projection is saved here.

  4. Click OKto close the dialog.

 

 

See Also

Map Coordinate System Overview

Introduction to Map Projections

Assign Coordinate System Dialog

Assign Coordinate System - Worksheet

Assign Coordinate System - Grid

Source Coordinate System - Map Layer

Target Coordinate System - Map

New Projected Coordinates

Custom Datum Definitions