Brooklyn College
City University of New York

Determining target distance is a necessity if triangulating distances. It's not crucial in photoscanning, but would nevertheless be a good parameter to know. The figure below shows an overhead view of a student measuring the height of the tyrannosaur's hip joint above the ground.

1. Student stands opposite character to be measured - the hip joint in this example.

2. Target distance (shown as a blue arrow) is the distance between the observer and the specimen. It can't be measured directly because you can't get inside the tyrannosaur's protective island. But target distance can be measured if you shift the arrow so it lies outside the island, as is the case for the dashed blue arrow.

3. To perform the shift as accurately as possible, trace your position toward the head of the animal in a line parallel to the animal's body axis (dashed yellow line). Using the joints between the floor tiles as a guide is a convenient way to do this. When you are clear of the island, you can make the measurement.

4. Determining target distance can be done simply in either of two ways: a) by pacing; or b) by measuring the length of one floor tile with a rule, and counting the number of floor tiles along the dashed blue arrow to the position of the hip (as represented by the interesection of the body axis (yellow dashed line) with the shifted target distance).