====== Track Measurements ======

This page describes how to track user [[glossary|Measurement]]s.

===== Listening ==== 

The Viewer SDK offers several Measurement related Signals that you can listen to.  
  * ''onMeasureUpdated'' : dispatched when the user updates a Measurement.
  * ''onMeasureCompleted'' : dispatched when the user completes a Measurement.

The user starts making a Measurement by clicking one of the measurement buttons in the Measurement Sidebar.  This action brings the viewer in Measurement mode.  Any viewer can be used to make registrations.

As the user makes registrations, the ''onMeasureUpdated'' signal is dispatched.

On completion, the ''onMeasureCompleted'' signal is dispatched. The user completes the Measurement by making the last registration (for a Measurement mode with a fixed number of registrations) or by making a registration using a double click.

Each measurement mode has its own focus or goal.

===== Using MeasureState =====

The ''MeasureState'' object describes the current measurement state : 
  * The list of registrations
  * The measurement mode
  * The measurement information properties.

===== Rendering =====

In a future update we are committed to provide an SDK function to retrieve ''MapObject'' instances that can be used to visualize the measurement on a third-party map.