# To measure points on a plane

In a conventional survey, use the Measure points on a plane measurement method to define a plane and then measure points relative to the plane.

To define a horizontal plane, vertical plane, or tilted plane you can select points in the job or measure new points. After defining the plane, measure an:

- Angle only measurement to the plane to create an angles and computed distance observation onto the plane.
- Angles and distance measurement to the plane to compute the perpendicular offset to the plane.

The type of plane calculated by the software depends on the number of points selected:

No. of points | Plane type
--- | ---
1 | Horizontal
2 | Vertical through 2 points
3 or more | Plane with residuals (for 3 points, the residuals will be 0). The plane can be a "Free" plane created as a best fit (typically tilted) plane through all points, or a "Vertical" plane constrained to a best fit vertical plane through all points. Tap the Free / Vertical softkey to toggle between the two modes.

1. Tap and select Measure / Measure points on plane.
2. To define the plane:
   1. Tap Add to select the point selection method and then select the point(s) to use to define the plane, or tap Measure to go to the Measure point screen and measure a new point to use in the plane definition. Add or measure at least enough points to define the required plane.
   2. Tap Calculate to calculate the plane.
   3. If the plane uses 3 or more points, you can tap Vertical to calculate a vertically constrained plane. If required, tap Free to recalculate the plane using the best fit through all points.
   4. Use the values in the Residuals column to identify any points that you want to exclude. Tap a row in the table to exclude or include a point and automatically recalculate the plane. The values in the Residuals column are updated.
3. Tap Continue to measure points relative to the plane.
4. Enter the Point name.
5. Select the Method to use for calculating the point:
   - Angle and distance calculates coordinates for the measured point as well as the distance from the point to the plane.
   - Angle only calculates coordinates for the observed point using the intersection of measured angles and the plane.

   When measuring with Angles and distance, configure the instrument EDM settings to turn on tracking mode to see the delta distance to the plane field update in real time.

6. Tap Measure.
7. Tap Store.