Construct geodetic features

The Construct Geodetic tool creates densified geodetic lines, circles, or ellipses. You can specify coordinate locations using the pointer, or enter measurement values for each coordinate parameter. This tool is available in the Modify Features pane.

Geodetic features account for the curvature of the earth and are spatially accurate and geodetically correct in any projection. Typically, geodetic features are used to model features or paths that span large distances, for example, an airplane flight path between two cities.

When you use this tool, consider the following:

• Editing densified geodetic geometry makes them nongeodetic. If you need to change or move a geodetic feature, re-create it instead.
• Unit formats include the Military Grid Reference System (MGRS), U.S. National Grid (USNG), and Universal Transverse Mercator (UTM).
• If your feature data consists entirely of two-point lines, an alternative to using this tool is to use the Two-Point Line tool with coded-value domains that specify the direction type in an attribute field named Azimuth Type.

To create a geodetic feature, complete the following steps:

1. Add your data and configure settings for editing.

   Confirm the feature layer you are editing is editable, the coordinate system assigned to the active map is suitable for the type of edits you're performing, and snapping is configured to help you work efficiently and accurately.

2. On the ribbon, click the Edit tab. In the Features group, click Modify .
3. In the Modify Features pane, click Construct Geodesic .

   To find the tool, expand Construct, or type Geodetic in the Search text box.

4. In the tool pane, check or uncheck the Show Preview check box.

   Checked	Preview the feature on-screen before creating it.
   Unchecked	Create the feature and do not show a preview.

5. Click the Template drop-down arrow and choose the layer in which to create the feature.
6. Click the Geodetic Type drop-down arrow and choose a geodetic feature type.

   Choosing a geodetic type determines the parameters that appear in the pane.

   Geodesic Line	The shortest line between any two locations on a spheroid, for example, a flight path between two cities. Also known as the great-circle distance when a spheroid (ellipsoid) is used. You can create this geodetic type only on line feature layers.
   Loxodrome	A line of constant bearing, or azimuth between two locations; not the shortest distance. Also known as a Rhumb line. You can create this geodetic type only on line feature layers.
   Great Elliptic	An elliptical arc between two locations defined by a plane passing through the center of the spheroid. Also known as a great-circle distance when a spheroid (ellipsoid) is used. You can create this geodetic type only on line feature layers.
   Geodesic Circle	A continuous line with every point on the path radially equidistant from one specified location. Its circular or noncircular shape depends on the coordinate system with which it is projected. You can create this geodetic type on line and polygon feature layers.
   Geodesic Ellipse	A continuous line whose sum of geodetic distances from a fixed pair of locations is a constant. You could use this to create a signal error ellipse. This is also known as a geodesic circle when the major and minor axes are the same length. You can create this geodetic type on line and polygon feature layers.

7. If you set the tool to create a Geodesic Line, Loxodrome, or Great Elliptic geodetic feature, complete the following steps.

   Choosing a unit format determines the parameters that appear in the pane.

   1. In the First Coordinate section, choose a unit format and type the coordinates.

      Alternatively, click Set Location and click the map to specify the coordinates using the pointer.

   2. In the Second Coordinate section, choose a format and type the coordinates.

      Alternatively, click Set Location and click the map to specify the coordinates using the pointer.

   To reset your values, click Reset .

8. If you set the tool to create a Geodesic Circle geodetic feature, complete the following steps:
   1. In the Coordinates section, choose a unit format and type the coordinate value for each coordinate parameter.

      Alternatively, click Set Location and click the map to specify the coordinates using the pointer.

   2. Click the Radius box, choose a unit format and type the radius value.

   To reset your values, click Reset .

   

   The unit format determines the parameters that appear in the pane.

9. If you set the tool to create a Geodesic Ellipse geodetic feature, complete the following steps:
   1. In the Coordinates section, choose a unit format and type the coordinate value for each coordinate parameter.

      Alternatively, click Set Location and click the map to specify the coordinates using the pointer.

   2. Click the Direction box, choose a unit format and type the direction value.
   3. Click the Major Axis box, choose a unit format and type a numeric distance value.
   4. Click the Minor Axis box, choose a unit format and type a numeric distance value.

   To reset your values, click Reset .

   

   The unit format determines the parameters that appear in the pane.

10. Click Create.