On the Wakulla-2 Expedition surveying is done automatically by a Digital Wall Mapper (DWM) mounted on a Diver Propulsion Vehicle (DPV). The DWM uses an Inertial Navigation System (INS) for determining the position and orientation of the DPV and a Sonar Measurement Device (SMD) that simultaneously measures thirty-two wall distances for determining cross sections. Data are gathered several times per second and the resulting wall points are spaced tens of centimeters apart.

Within the DWM, data from the INS, the SMD, three pressure sensors, and a thermometer are stored in an on-board computer. When the DPV returns to the surface the data are downloaded to a Personal Computer (PC). The PC reformats and writes the data to a zip disk which is then transferred to a Silicon Graphics Inc. (SGI) workstation.

Nine separate programs, written in ANSI C and using SGI-GL for graphics support, comprise the software suite on the SGO workstations. These nine programs provide the following functions:

• Allow the visualization of the raw data from the DWM for inspection and for editing any obvious problems.
• Allow the conversion of traverse line data from the INS, in the form of Cartesian coordinates referenced to the start point of the survey run, to the master Cartesian coordinate system established for the cave.
• Using information from the INS, to convert the radial distance sonar measurements from the SMD to Cartesian coordinates of wall points referenced to the master Cartesian coordinate system established for the cave.
• To allow the conflation of data from multiple survey runs to improve the accuracy of passage morphology.
• To convert random passage wall points to sequential cross sections along the cave passages, in order to maximize the efficiency of rendering the passages on the SGI workstation using shaded polygons.
• To present on the screen of the SGI an interactive 3D map of the cave and its surface environs, for research, interpretation, and study.

About 50,000 lines of custom C-code are required to perform these functions.

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