side shot

A side shot is a survey measurement taken from an established station to any point that lies outside the main traverse line. Unlike traverse stations, which are chained together to form the skeleton of the survey, side shot targets are typically stationary features, boundaries, or objects whose positions must be recorded on the finished map but need not carry the survey forward. A surveyor sets up at a known station and takes a bearing and distance (or angle and distance) to the off-traverse point, capturing its location relative to the control network.

In classical surveying, side shots are taken from the transit or theodolite to detail such features as building corners, fence lines, tree lines, watercourse banks, property boundaries, or utility poles. The measurement usually consists of a horizontal angle from the traverse line and a perpendicular or radial distance. Modern total stations automate this process: the instrument records both angle and slope distance, then calculates the point's coordinates directly. In some methodologies, side shots are also called detail shots or offset shots, particularly when the measurement is a perpendicular offset from the traverse line itself.

Common errors and limitations

The primary risk with side shots is accumulation of small angular or distance errors that distort the map beyond the accuracy needed for the project. Because side shots do not loop back to the traverse, errors in bearing or distance have no check. Poor visibility, unstable instrument setup, or careless tape measurement can introduce significant positional error. Surveyors therefore often limit the length of side shots and take them from stations with the strongest intersection geometry; a point located from two distant stations is more reliable than one located from a single station far away.

Side shots are economical when used selectively. Shooting every tree or shrub near the traverse is wasteful and produces cluttered, unusable maps; selecting features that affect land use, property lines, or infrastructure is the practical standard. In urban surveys, side shots might pick up building setbacks or pavement edges. In rural work, they might locate isolated structures, water features, or vegetation boundaries. The density and selection of side shots depend entirely on the purpose and scale of the finished map.

The term reflects the physical reality of the work: the shot is made to the side of (or away from) the main traverse line, in contrast to forward shots along the traverse itself. This discipline remains central to both traditional chain-and-compass surveying and to modern GPS and total station work, where the traverse provides the framework and side shots fill in the visible detail needed for a usable map.