To use control points in an alignment, they must be measured in the images that observe them using the Image Measurements tool on the Alignment tab.
You can import control points, their manual image measurements, and their control point roles from Inpho .prj files if available.
Measure control points
To measure control points, complete the following steps:
- In the Project Tree pane, select the alignment containing the control points you want to measure and click the Alignment tab.
- On the Alignment tab, click Image Measurements
.The Image Measurements view appears.
- On the Image Measurements view, in the Control Points table, click the row number of a control point you want to measure.
The images containing the chosen point are listed in the Image table. The first image in the table is shown in the Image viewer.
Note:
If you don't want to use a control point in the alignment, click Enable/Disable
to exclude the control point from the alignment process. A crossed gray ring 
appears indicating the control point is excluded from the alignment. Click Enable/Disable again to include the control point in the alignment. - In the Image viewer, click the exact location of the control point in the image and go to the next image.
Note:
To go to the next image, you can use keyboard shortcuts, use the navigation buttons on the toolbar, or click the image in the Image table.
Repeat this step for all the images in the table. Alternatively, you can set one of the measurements as a template to request image measurement suggestions in the remaining images.
Note:
You must make at least two image measurements for a control point to be used in an alignment or to set an existing measurement as template.
Tip:
To change a measurement, you can click a new location in the image or remove the measurement by clicking the Remove button
on the toolbar. - Repeat steps 3 and 4 for each control point you want to include in the alignment.
The control points are measured and ready to be used.
You can process the alignment once all the necessary control points have been measured.
Request image measurement suggestions
Image measurement suggestions are generated using an image template, the image orientations and the previous image measurements.
To request and use image measurement suggestions complete the following steps:
- After two or more manual measurements are made, select one of the images with a measurement in the Image table and click Find Suggestions
on the toolbar.A template symbol
appears in the Image table, in the Status column. Suggestion symbols 
appears in the Status column where image suggestions are generated. - Click the row of an image with a suggestion to see it in the Image viewer.
- Click Accept
or press the Spacebar to accept the suggestion.Note:
You can click Accept All
on the toolbar to accept all available suggestions. - Optionally, you can use a different image measurement as template to get more suggestions. To do so, select the new image in the Image table and click Find Suggestions on the toolbar.
New measurement suggestions are generated based on the new template.
Keyboard shortcuts
You can use keyboard and mouse shortcuts to navigate, browse, and measure points.
Navigation in 2D
Use keyboard shortcuts in the image viewers for help with navigating the images.
| Keyboard shortcut | Description |
|---|---|
Middle drag | Pan. |
Middle roll wheel | Zoom in and out. |
Right hold | Continuous zoom. |
Navigation in 3D
Use keyboard shortcuts in the globe viewers for help with navigating 3D scenes.
| Keyboard shortcut | Description |
|---|---|
Click | Identify features in a pop-up window. |
Click drag | Pan. |
Middle drag | Rotate and tilt the view. |
Middle roll wheel | Zoom in and out. |
Right hold | Continuous zoom. |
Image measurements
Use keyboard shortcuts in the Image viewer of the Image Measurements tool.
| Keyboard shortcut | Description |
|---|---|
Click | Make an image measurement. |
Shift+click | Remove an image measurement. |
Spacebar | Accept suggestion and go to next image. |
Browse tables
Use keyboard shortcuts for help with browsing tables in the Image Measurements tool.
| Keyboard shortcut | Description |
|---|---|
F | Go to next image in the Image table. |
B | Go to previous image in the Image table. |
Shift+F | Go to next point in the points table. |
Shift+B | Go to previous point in the table. |
Role of a control point
A control point can have two roles: It can be used as a ground control point (GCP) and a check point (CP). GCPs are used in the alignment processing. CPs are used to assess the quality of the alignment results.
Note:
The role of a control point is specified per alignment. This allows you to use different roles for the same control points in different alignments.
If control points are imported from an Inpho .prj file, the roles of the control point are imported as well. In all other cases, control points are assigned the GCP role by default.
Change the role of a control point
To change the control point role, complete the following steps:
- On the Image Measurement view, in the Control Points table, select the control point to edit.
Tip:
You can select and deselect individual control points by pressing the Ctrl key while clicking. To select and deselect groups of control points, press the Shift key while clicking.
- On the Control Points table toolbar, click Set Role
and choose a role from the drop-down menu.
The role of the selected control point is updated and visible in the Control Points table.
You can process the alignment to update the alignment results.
Image measurement status
A control point must have at least two image measurements to be included in the alignment process. The status of a control point is represented by a symbol that indicates the number of images it has been measured in.
The image measurement status symbols indicate the following:
—A point has fewer than two image candidates and cannot be used in an alignment.
—A point has two or more image candidates but no image measurement.
—A point has two or more image candidates and one image measurement.
—A point has two or more image measurements, and there is at least one image candidate that is not measured.
—All image candidates have measurements.- —A disabled point that will not be used in alignment.