Ellipsoid Definitions

The DataSourceEditor GUI allows you to add, change and delete user-defined Ellipsoids, and to view all Ellipsoids. Optionally, you can pass ObjectType.Ellipsoid into the DataSourceEditor constructor to filter the editor window to only show Ellipsoids.

Create a new Ellipsoid

1. Create a DataSourceEditor object and display it with the Show method.
   
   

2. In the right-hand pane, right-click and select New Object or click the Add button below the pane.  A new blank Ellipsoid Editor dialog will open.  There are two tabs on the Ellipsoid Editor:
   

   Identification
   

   The Identification tab is used to name the object and associate identifying codes with it (if applicable).  

   • The Name field is where you need to enter the appropriate name for the definition; the name entered is the name that will be used to select the object in the main list.  
   • The Remarks field can be used to add notes on a definition and is optional.  
   • The Identifiers list may be used to add identifying codes for an object that may be referenced in other databases. The GC code is a unique identifier assigned by GeoCalc which cannot be altered. To enter additional codes, right-click in the space below.  
   • Deprecated may be checked to indicate an object is no longer being used, either because there are errors in the definition, or because it has been superseded by another object. If this is checked, you will be provided with a date picker to set the date on which the object was deprecated. This will default to the current date.
     
     
     

   Details
   

   The Details tab is used to define the object's parameters.  For Ellipsoids you must enter the parameters for the Semi-Major Axis and Semi-Minor Axis (often noted as "a" and "b" respectively).

   Define the linear units for the axes by selecting a predefined unit in the appropriate fields.  The Inverse Flattening (often noted as "1/f) will automatically calculate in the field below. Alternately, you can make the Inverse Flattening definitive by enabling the check box at the bottom. You can then manually enter the Inverse Flattening rather than the Semi-Minor Axis parameter. The Semi-Minor Axis may not be greater than the Semi-Major Axis, nor may either be zero.

   If a pair of values are invalid, the fields will be highlighted in pink to reflect this.

3. Click OK to close the Ellipsoid Editor.

4. To save the definition permanently, click the Save button on the right hand side of the DataSourceEditor dialog.

5. Click OK to close the DataSourceEditor dialog, your new definition is complete and may be used within GeoCalc.

Change an existing Ellipsoid

1. Create a DataSourceEditor object and display it with the Show method.

2. Select the object from the Ellipsoid list.
   

   You can only edit objects shown in blue.

3. Double click the object you want to edit to open its definition.

4. Change any of the values and press the OK button.

5. To save the definition permanently, click the Save button on the right hand side of the DataSourceEditor dialog.

Delete an existing Ellipsoid

1. Create a DataSourceEditor object and display it with the Show method.

2. Select the unit from the Ellipsoid list.
   

   You can only delete objects shown in blue.

3. Select the object, right-click it and select Delete Object or click the Trash Can button below the object list.

4. To save the deletion permanently, click the Save button on the right hand side of the DataSourceEditor dialog.