4.2 Labeling Objects in the Rover’s Environment

When data arrives from the rover, it is useful to assign names to the points of interest in the vicinity of the rover. These names facilitate planning discussions and are used within Maestro to specify positions and directions within Activities that require this information. A Maestro user names a position in the rover’s environment by creating a Feature or a Target. Features and Targets are related concepts with important differences, described in Section 4.2.1. Features and Targets are created in different ways depending on whether there is range information available for the point of interest, that is, information stating how far the point of interest is from the rover. The impact of the availability of range information on Feature and Target creation is discussed in Section 4.2.3.

4.2.1 Features versus Targets

A Feature refers in a general manner to a whole object in the environment, such as a rock, a cliff, or a patch of soil. For instance, if you decide that a particular rock looks like a big melon and want to name it “Cantaloupe”, you would create a new Feature with that name at the location of that rock, as shown in Figure 4.3. When discussing what the rover should do at a high level, scientists usually refer to Feature names. For instance, someone might say that the rover should drive toward Cantaloupe on the next sol. Features are not intended to refer to a particular location on an object and cannot be used to specify a position for an Activity in Maestro. Targets, described below, are used for this purpose. Features are displayed in Maestro downlink views as a pink circle.

Figure 4.3: An example of a Feature and a Target.

A Target refers to a precise location or direction in the vicinity of the rover. Where a Feature names a whole object, a Target names a specific spot on that Feature that is significant for some reason. For instance, let’s say that the rock named Cantaloupe appears to have an irregular spot on the side that would be a good thing to take a picture of. You would create a Target at that location and give it a name that describes its appearance, such as “Dent”. A Target must be associated with a Feature when it is created, which means that Maestro will not allow you to create a Target until there is at least one Feature in the Session. Targets can be used to specify the location for an Activity, and are generally aren’t built until it a Maestro user decides that they would like the rover to execute an Activity on a position within a Feature. Targets are displayed in Maestro downlink views as a red circle.

4.2.2 Creating Features and Targets

Before you can create a Feature or Target, you must first have a plan loaded in the Uplink browser, either by following the steps in Section 4.1 to build a new plan or the steps in Section 4.3.5 to load a saved plan. Features and Targets, when created, are added to the Session associated with the plan that is currently selected in the Uplink browser (for more information on Sessions see Section 4.1). You also need to follow the steps in Section 3.1 to load a data product in the Downlink browser. Once you have a plan loaded in the Uplink browser and a data product loaded in the Downlink browser, you are ready to create a Feature or a Target. Note that if no Features have been built in the selected plan’s Session, you must create at least one Feature before you will be able to create a Target.

Creating a Feature

Begin by adjusting the data product that you are viewing in the Downlink browser until the object you would like to name is visible. Click somewhere on the object to move the Point of Interest glyph to the object. As discussed in Section 3.3.4, the Point of Interest glyph is represented as a cross () if there is no range data available and as a circle () if there is range available. In this Section we will assume that you have found a position with range data as shown in Figure 4.4. In the next Section we will describe how the Feature and Target creation process changes when no range data is available.

Figure 4.4: Adding a Feature

Once you have clicked on a suitable position, select the Add Feature menu item within the Action menu on the Downlink browser menu bar as shown in Figure 4.4. This will cause the Add Feature dialog to be displayed as shown in Figure 4.5. Two values must be entered in this dialog, described in the table below:

The custodian field informs other users who to contact with questions about this feature. You should enter your name in this field, or the name of the group you are working with. Once you have entered a custodian name once, Maestro remembers the value you provided so that you don’t have to type it the next time you add a Feature or Target. When you click the OK button, Maestro will create the Feature and display it at the correct location in the view.

Figure 4.5: The Add Feature dialog

Creating a Target

The procedure for creating a Target is almost identical to the procedure for creating a Feature. Once you have clicked on a suitable location, select the Add Target menu item from the Downlink browser Action menu. It is located directly above the Add Feature menu item, as shown in Figure 4.4. When you select this menu item, the Add Target dialog will be displayed as shown in Figure 4.6. The Add Target dialog has three fields that must be filled out, described in the table below:

Figure 4.6: The Add Target dialog

If while you are filling out the fields of the Add Target dialog you discover that a suitable Feature for the Target does not exist, you must cancel the Add Target dialog and add the required Feature before continuing. Maestro does not allow you to associate a Target with a different Feature after it has been created. When you click OK, Maestro will create the Target as specified and display it at the correct location in the view.

4.2.3 Creating estimated Features and Targets

In the last Section, we assumed that the location you had selected as a Point of Interest had range information, meaning that Maestro knows the distance from the rover to the selected point. Unfortunately, range data is not available for every point in every image for a variety of reasons. Despite the lack of range data, it may still be desirable to build a Feature or Target at these positions anyway. To address this need, Maestro allows the user to create estimated Features and Targets.

When a user selects the Add Target or Add Feature menu items from the Downlink browser Action menu while the Point of Interest Glyph is at a position without any range data, a special dialog is displayed. Figure 4.7 shows the Add Estimated Target dialog. The Add Estimated Feature dialog is identical except that it does not ask the user to select an associated Feature. In addition to warning the user that they are about to create an estimated Target, the dialog provides some special information to the user and requests some additional information as well. The new fields in the dialog are described in the table below:

The first two fields (azimuth and elevation) are provided for informational purposes only and cannot be edited. The estimated range field is a critical field that requires the user to provide an estimated distance to the Point of Interest Glyph using their own knowledge of the environment and tools in Maestro. Usually, an appropriate value for this field can be determined by clicking on points near the desired Target position that do have range before selecting the Add Target menu item. While it is good to enter an accurate value, even a very approximate value is sufficient in many situations. If the Point of Interest Glyph is above the horizon, then select the “Infinity” option rather that attempting to enter an estimated range. When the OK button is clicked, Maestro will create the estimated Target and display it at the correct position in the view. Estimated Features and Targets are represented by pink and red crosses, respectively.

Figure 4.7: The Add Estimated Target dialog.

4.2.4 Viewing information about Features and Targets

As you and other Maestro users you are collaborating by adding Features and Targets to a Session, they will be displayed at the correct position in all Maestro downlink views. In addition, you can view a list of all created Features and Targets and access details about them using the Targets tab of the Uplink browser.

To access the Targets tab, make sure you have a plan loaded and then click on the tab labeled “Targets” near the top of the Uplink browser as shown in Figure 4.8. This will display a hierarchical list of all the Features and Targets in the Session for the loaded plan. Features are displayed as folders which contain their associated Targets. The Targets Tab displays the name, custodian, and notes for each Target and Feature and also provides a Visible checkbox that allows the user to hide and show individual Features and Targets. To hide a Feature or Target, click once on its row to highlight it, then click on the Visible checkbox on that row to uncheck it. This will cause the highlighted Feature or Target to be hidden in all Maestro Downlink views. To show the Feature or Target again, repeat the process to re-check the Visible checkbox.

Figure 4.8: The Targets tab of the Uplink browser

Additional information on each Feature and Target shown in the Targets tab is displayed in the Details dialog when a Feature or Target is selected. Figure 4.9 shows the contents of the Details dialog when the Target called “Eye” from Figure 4.8 is selected. The Details dialog is a companion window to the Uplink browser that is visible by default. If it is not visible, you can cause it to be displayed again by clicking on the Details icon in the Uplink browser toolbar.

When a Target is selected, the Details dialog will display all of the information in the Targets tab plus several additional read-only values. Among these are the x,y,z position of the Target in meters, the x,y, and z components of the surface normal at the location of the Target, and the date when the Target was created. The custodian and notes fields can be modified in the Details dialog. When modifying a field in the Details dialog, note that your change will be applied if you press Enter or click somewhere else in the application.

Figure 4.9: The Details dialog showing information about a Target.