Output can be used for structural assessment, pre and post-rehabilitation analysis, hydrological surveys, as well as general condition assessment. SPiDER weighs less than 30 pounds and can be hand carried to difficult to access sites. Additionally, SPiDER does not require a truck or data/power cable for operational use. Scanning data is recorded on the unit. SPiDER can calculate its position in the manhole shaft by using its internal sensor data to measure its incremental motion. This technology frees manhole scanning from problems associated with inaccurate, poorly calibrated cable counters and poorly managed cables.