Journal of Surveying Engineering

Five optical theodolites of different designs and least counts are compared for accuracy in reading horizontal angles. A subtense bar of an accurately known length and a Wild T3 precision theodolite are used for this purpose. Subtended angles are first measured using the Wild T3. These are then remeasured using each of the test instruments. The root‐mean‐square‐error values of angle measurement are then computed as standard deviations. The best accuracy values are obtained with the double‐reading micrometer theodolites. However, in almost all cases considered, the optical scale‐reading theodolites give accuracy values approximating those obtained with a single‐reading micrometer type of instrument.

A technique is developed for the three‐dimensional alignment of a straight line from stations independent of the line itself. If a line is given by two points, no instruments are required to occupy the line. Alignment is accomplished by forming two planes, their line of intersection being the given line. Each of the two planes contains the two given points and a theodolite station chosen independent of the given line. The accuracy obtained with this technique is equivalent to that of horizontal alignment using theodolites.

There is a great deal of interest in geofacilities information systems (GIS's) among utilities and state and local governments since the early 1980s. GIS's are corporate data bases that maintain virtually all of a company's installed plant (facility) assets within the framework of a geographic X‐Y grid‐coordinate system. Wisconsin Public Service Corporation (WPSC) has developed a GIS to maintain both gas and electric facility information. In addition, WPSC's GIS is designed to maintain facility connectivity relationships for network modeling and graphics information for mapping. Since the GIS is X‐Y‐coordinate‐based, three key issues central to the base map and X‐Y‐coordinate grid selection were identified and addressed very early in the GIS design. Those three issues are: Base‐map availability/cost, base‐map accuracy, and grid X‐Y‐coordinate selection. The payback for any GIS is through the use of applications (practical uses of the GIS information). Several electric applications are briefly discussed to demonstrate the usefulness of a GIS.

There have been significant changes in the way right‐of‐way plats are prepared by the Wisconsin Department of Transportation (DOT) in the last 60 years and particularly over the past decade with the advent of computer‐aided design drafting (CADD). The right‐of‐way (R/W) plat is Wisconsin DOT's permanent record of lands owned for highway purposes. As such, it must clearly document land acquisition limits and provide a historic record of their relationship with established government land monuments. The age of electronics came upon us at the same time property owners and our negotiators were asking for more information presented in a highly graphic, easily understood form for the lay person. More frequent changes in acquisition limits were occurring during negotiations. Complex plats were subject to regular revision. The computer‐aided design drafting system (CADDS) allows us to meet the demand for greater detail and for significantly increased data on our plats. It allows us to produce highly graphic plats that meet the needs of their many users, and yet, are easily amendable when the need arises.