Convert orthometric height Z values to feet using an Arcade expression

Summary

In ArcGIS Field Maps, the altitude reads the height above ellipsoid value for a point in meters, not the orthometric height in feet. Often customers using Field Maps with a GNSS receiver collect data related to the orthometric height of their data points. The orthometric height is stored in the z-value of the Geometry. 

Sometimes users may also want to convert the units collected in the value to feet, for example. The following steps provide an Arcade expression to display the orthometric height as an attribute value, and how to convert that value to feet.

Procedure

The following Arcade expression displays the orthometric height as an attribute value and converts this value from meters to feet.

var geom = Geometry($feature)
if (IsEmpty(geom)) {
return null
} else {
return geom.Z*3.28084
}

Note:
The value "3.28084' may need to be adjusted if the user's Field Maps is not recording the data in meters originally. And additionally, if the user would like to leave the orthometric height in meters they can omit the "*3.28084" to display the orthometric height as recorded in Field Maps.

If it is desired that the values to be adjusted for mobile workers in the field who are collecting data through ArcGIS Field Maps, the expression can be added to the Field Maps form:

1. In the Field Maps Designer web app, navigate to the form and click it to open the Properties pane.
2. In the Logic section, select the Expressions button next to the Calculated Value check-box.
3. Click +New Expression.
4. Add a Title for the expression and copy and paste in the Arcade function from above.
5. Test the expression by selecting Run.
6. Click Done when the expression is working as desired.

Alternatively, this expression can be applied to a web map through Map Viewer pop-ups:

1. Open the web map in Map Viewer.
2. Select Pop-ups from the icons on the right.
3. Add the altitude field to the pop-ups.
4. Select Attribute Expressions and then +New Expression. 
5. Add a Title for the expression, then copy and paste the expression above.
6. Test the expression by clicking Run.
7. Click Done when the expression is working as desired.