There are two non-column specific features that help when dealing with tables. These are dealt with in more detail in the Point Table chapter but as reminders we mention them here too:
• Use Table Configurations to get the specific columns you need for the job. You can use some of the configurations that come installed with the program but you can create your own or edit those pre-installed ones.
• When you find a suspect point and want to manipulate it or study it on its Photographs, first select it (or two or more points) and then use the "Open Photos Showing Selected" right click menu item. This will open all photos showing this point selected. Holding down the Ctrl button while the clicking this tool will close/or keep open other photos, depending on the Preference setting (i.e., Ctrl will do the opposite of the Preference setting).
Here are a list of specific columns of the Point Table and how they can be used for project assessment:
• Photos – sort by this column to see which points are on only one or two photos. The one photo points will have no 3D position (unless they are control points or part of an Axes Constraint) and the two photo points have no redundancy so their accuracy is suspect.
• Tightness – sort by this column to find the points with the largest tightness values. Study how these points with large tightness are marked (or their photos are oriented). Also look at the values of the Tightness (unit) column to see if the values seem reasonable for your desired accuracy. E.g. if you want 1.0mm accuracy then you should have tightness that are no more than 3.0mm (and preferably less than 1.0mm).
• Angle - sort by this column to look for points with low maximum angles. Points with angles less than 15 degrees are suspect for good accuracy. If a large number of points in the project have low angles then the whole project accuracy is suspect.
• RMS Residual – sort by this column to verify average marking precision for the points. Points with the largest RMS Marking Residuals have the worst photo point marking.
• Largest Residual – sort by this column to look for points that may have a Marked Point that is incorrectly placed. You can use the "Largest Photo Residual" column to figure out which photograph has the worst mark for this Object Point. See Marking Residual.
• XYZ Precision – sort by this column to verify that the Processing has not flagged any points as low accuracy (usually due to poor photo angles or poor marking). Points with the largest precisions are the worst. Also look for the X, Y or Z precisions being largely different from the X, Y, or Z precision values (which may indicate a poor camera geometry). For further discussion of the meaning of precision refer to Accuracy and Precision in the Glossary.
• Precision Vector Length – sort by this column to view the points with highest precision vector lengths as an indicator of point quality. The Vector Length is the result of a point's X, Y and Z Precision.
• # Constraints – review this column to see if the point is constrained (which may lead to poor accuracy or inability to solve the point if the constraints conflict or over-specify the point).
• Use in Processing – review this column to ensure the point is being handled in Processing or not as desired.
• Frozen – review this column to ensure the point (or any points) are not frozen (unable to move in xyz) which may lead to the inability to process or may cause model warping if the project has changed considerably after the points were frozen.