123 Programmetry FAQs

FAQs Questions are assigned a number for easy reference.

Q1: Why do I need photogrammetry?

A1: It is possible that you do not need photogrammetry. However, if all of the distance information you will need has not be obtained, and the following has occurred, you will need photogrammetry:
New roadway lines through site,
Roadway has been resurfaced,
Time, weather, and traffic have had an errasing effect on the site,
Involved vehicles and debris have been removed from site, and
All the above plus those unique situations everyone has experienced.

Q2: Why do I need a certified photogrammetry consultant?

A2: Your photogrammetry consultant must be qualified by the Court and a certiffied consultant will have the qualifications. Also, skill (experience) is very important in photogrammetry and it is most likely that a certified photogrammetrist will have the experience required to have developed the skill required.

Q3: Is it important to have a site-measurement survey (SMS)?

A3: The importance of a SMS is the accuracy of the distances provided by the SMS. The SMS includes an area far greater than the immediate site area and thus provides accurate distance information in the photography taken from many, many, different locations. The 2D plot compiled using the SMS, and distances obtained from the photogrammetry analysis, provides the reliable dimensional information, on a single piece of paper, that can be used by other consultants in their analysis work. In other words, yes it is important to have a SMS.

Q4: Can the photogrammetry analysis be incorrect?

A4: Yes, and that is one of the reasons to have a skilled photogrammetry consultant. For each technique there are methods to use to determine if an error (blunder or otherwise) has occurred, and the skilled consultant in photogrammetry will be able to apply these methods.

Q5: Is it important to know the camera data (parameters) for the photography?

A5: Yes, there are time when it is important to know the camera parameters, however, it is not always available. There are photogrammetry techniques where the consultant must know those parameters, or a very close approximation, in order to arrive at an anlaysis solution. There are also photogrammetry techniques where the consultant can either obtain the required information from the geometry of the photo/image, or the parameter data is not required for the technique being used. The skilled consultant will know which technique will work best with the geometry of the photo/image and available data.