This feature is extremely useful for users to compare the progress of a site over two survey missions and identify and understand changes that have occurred between the surveys. You can compare missions in two ways:

• Split view: This view displays the layers from the two selected snapshots superimposed on each other with a slider to show/hide the other layer.

• Side by side view: This view displays the layers from the two selected snapshots next to each other so that they can both be viewed at the same time.

Split View

1. Open the site for which you want to compare two different surveys and click Compare Missions.

Compare Missions

The Compare View opens with the Split View displayed by default.

2. From the date dropdown, select the dates for the snapshots you want to compare.

Compare Missions - Select Date (Split View)

3. Use the slider to compare the status of the site for the two dates.

   For example, if on the left side, you are viewing the orthophoto for a site taken on an earlier date than the orthophoto visualized on the right side, moving the slider slowly to the right side can help you see the actual progress on the site. Moving the slider to the right will show you the ‘before’ image (site status at earlier date) and moving it to the right will show the ‘after’ image (site status at later date).

Slider Control

To compare other layers or overlays such as surface models or contour maps from two snapshots, click the Layers or Overlays icon and select the layer or overlay to be visualized.

Comparing Layers in Split View

When comparing a layer or overlay, it is recommended to hide all other layers/overlays for better visualization. For more information on viewing 2D data, click here and for viewing overlays, click here.

Side By Side View

1. To compare missions side by side, on the top right, click Side By Side. The Side By Side view is displayed.

Compare Missions - Select Date (Side By Side)

2. From the date dropdown, select the snapshots you want to compare. The side by side view allows you to look and compare the before and after status of a site on a single screen. You can compare other layers and overlays or add annotations as required.

Exiting Compare View

To exit Compare View, from the top right, click Exit Compare View.

Exit Compare View