Measuring Remote Distance
Offset Calculations
A situation was recently brought to my attention, where a consultant was asked to inspect a tree on a property adjacent to, but not owned by his client. He was not allowed to enter the neighbor's property, so had to make the inspection from a distance. In addition to the usual problems of examining the tree, the question arose of exactly where the tree was located.
A little geometry and algebra can solve this problem. By taking several measurements on the adjacent (client's) property, the distance of the tree from the property line can be estimated quite accurately.
The following diagram shows the steps needed to complete this simple task. Note that the lines AD (property line) and BC (the baseline) must be parallel.
The Problem
Determine the distance of the tree from the property line, without going across the line.
The Solution
- Measure a distance perpendicular to the property line (from A to B).
- Measure a distance parallel to the property line (from B to C).
- Sight back to the tree from point C, and mark the location of D on the property line.
- Measure the distance from D to A.
You should now have the measurements for AB, BC, and AD.
Here's the formula: 
