The tools currently available to collect the data and build the database include the following:

Survey information is collected using a pair of specially designed recording carts fitted with an electronic theodolite, computer and power supply. The cart is positioned in a room at a location of maximum visibility and backsights taken to establish its location and orientation. The desired points are then collected and automatically entered into the database. At any time these points can be used to generate all or part of the model so that it can be checked against reality before the instrument is moved to its next location.

Measurements can also be collected using standard running dimensions supplemented with polar cylindrical coordinates established using a radially calibrated plane-table (image 343k), supplied with the software. Distances can be collected using a steel tape or the DISTO visible laser (image 343k) device marketed by Leica.

  • Some Omphalii

    Existing CAD drawings and/or databases can be processed into linked models with a minimum of effort even if they were created on incompatible systems. This is done by extracting drawing intelligence directly from the .DWG or .DXF file into the database and regenerating the drawing using CART.

    Paper drawings can be scanned and processed using Autocad and Tern-OVLY, with the CART data entry add-on. Instead of drawing lines over the raster image individual points are identified and linked to an object name to create a CART database from which the model can be generated.

    Photographs can be processed in the same way using the ASR rectification program, to create scaled photographs from which a CART database can be created using the interface provided by ASR.

    Last change: April 8, 1998 (Steve Nickerson)