Plotter

Abstract: NRCVAX is a complete system of programs, covering all aspects of crystal structure analysis from data reduction to the presentation of results. The system, which is written in a `neutral' Fortran 77, presently exists in two forms. The first runs on a VAX computer under VMS, on an 80386 PC under UNIX and under IBM VM/CMS and MVS/TSO. The second is an adaptation which runs on PC-XT, AT, PS/2 and comparable microcomputers under MS-DOS. The two versions differ somewhat in structure, but very little in code, operation or functionality except for the graphics. The many options of the programs can be selected in a highly interactive manner and because of this the system is very flexible. Most options are assigned default values, however, and it is usually safe to run the routines with a minimum of user input using the defaults. The system will accept data from a wide variety of sources and has interface routines for several other systems. Graphics in the VAX/UNIX version are based on the widely available Tektronix 4000 series protocol, while the microcomputer version supports most common display adapters. It is also possible to prepare files for a variety of plotters, dot-matrix printers and laser printers. Source code is distributed and it should not be difficult to adapt the system to any computer with virtual memory and a Fortran 77 compiler.

Abstract: HYSEP is a computer program that can be used to separate a streamflow hydrograph into base-flow and surface-runoff components. The base-flow component has traditionally been associated with ground-water discharge and the surface-runoff component with precipitation that enters the stream as overland runoff. HYSEP includes three methods of hydrograph separation that are referred to in the literature as the fixed-interval, sliding-interval, and localminimum methods. The program also describes the frequency and duration of measured streamflow and computed base flow and surface runoff. Daily mean stream discharge is used as input to the program in either an American Standard Code for Information Interchange (ASCII) or binary format. Output from the program includes tables, graphs, and data files. Graphical output may be plotted on the computer screen or output to a printer, plotter, or metafile.

Abstract: Circular arcs can be drawn on an incremental display device such as a cathode ray tube, digital plotter, or matrix printer using only sign testing and elementary addition and subtraction. This paper describes methodology for producing dot or step patterns closest to the true circle.

Abstract: A procedure for digital image correlation is described which is based on least squares window matching. The immediate aim is high precision parallax assessment, point transfer, and point measurement. Experiments and theory have confirmed the high accuracy potential of the method. By implementation of charge coupled device (CCD) video cameras in an analytical plotter, an experimental hardware and software configuration has been established with which the operational on line application of digital image correlation for conventional photogrammetric measuring tasks can be tested. First results of calibration and performance of the system are presented. They allow optimistic conclusions as to the further development and practical application of digital image processing in photogrammetry.