IThis file was created by scanning the printed publication. Text errors identified by the software have been corrected; however, some errors may remain. Two computer programs to help timber-harvest planners evaluate terrain for logging operations are presented. The first program, VISUAL, produces three-dimensional perspectives of a digital terrain model. The second, SLOPE, produces map-scaled overlays delineating areas of equal slope, aspect, or elevation. Both programs help planners familiarize themselves with new terrain and obtain a general feel for the land. Included are descriptions of operating procedures, descriptions of major algorithms, suggested applications, and limitations. Guides for the programs are available from the authors.
A skyline-logging simulation model designed to help planners evaluate potential yarding options and alternative harvest plans is presented. The model, called SIMYAR, uses information about the timber stand, yarding equipment, and unit geometry to estimate yarding co stand productivity for a particular operation. The costs of felling, bucking, loading, and hauling are not considered. Included are a description of the input requirements for SIMYAR, descriptions of the major algorithms, suggested applications, and a discussion of limitations. A users guide is available as an appendix to this publication.
Twito, Roger H.; Mifflin, Ronald W.; McGaughey, Robert J. The MAP program: building the digital terrain model. Gen. Tech. Rep. PNW-GTR-200. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station; 1987. 22 p.PLANS, a software package for integrated timber-harvest planning, uses digital terrain models to provide the topographic data needed to fit harvest and transportation designs to specific terrain. MAP, an integral program in the PLANS package, is used to construct the digital terrain models required by PLANS. MAP establishes digital terrain models using digitizer-traced contour lines from topographic maps, which are, in turn, processed into an elevation grid and stored in matrix form. MAP builds continuous digital terrain models that can cover large planning areas and builds them to any elevation grid spacing desired. Though the MAP method does not always result in digital terrain models that are a perfect equivalent to the topographic map, they should be adequate for planning. A guide giving detailed operating instructions for the programs is included.The MAP program creates the DTMs used by the rest of the PLANS programs. DTMs are created in three basic operations: 1. Establishing the boundary of the DTM. 2. Digitizing the DTM's contour lines. 3. Converting the digitized contour-line data into a DTM. The topographic map of the project planning area is the source from which DTMs are built. The physical size of the topographic map(s) and the resulting DTM coverage area require careful preparation before building the DTM, especially when large areas are being planned for. Usually, large areas have to be subdivided into smaller DTM units. Subdivision is required when: 1. The DTM coverage area is larger than the digitizer tablet, or 2. The DTM coverage area cannot, as a single unit, meet the desired gridline spacing When subdivision is required, the DTM coverage area is divided into equal-size, rectangular DTM units. Later, up to six adjacent DTM units can be loaded and combined into an enlarged DTM when the design programs in PLANS are used.The first step in building a DTM is to delineate the planning area on the topographic map 1/ by carefully enclosing the planning area within a rectangle that defines the DTM coverage area. Next, the user enters the measured dimensions of the rectangle and the desired gridline spacing for the DTM (additional detail on gridline spacing is provided in the appendix), and the program determines if subdivision is required. If subdivision is needed, the program calculates the DTM-unit size necessary to obtain the desired gridline spacing and instructs the user on locating and marking the subdivision boundaries within the DTM coverage area.After the DTM unit is enclosed in a rectangle, elevation data can be entered via the digitizer. First, the location of the DTM unit on the digitizer tablet is established by digitizing the lower left corner of the unit and a point on the lower boundary. Then a process-control menu is taped to the digitizer t...
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