United States Department of Agriculture Forest Service eNumber En gi n rin g Field Notes Volume 13 4 April 1981 Engineering Staff Washington LI S D.C. Engineering Technical Information Field System Notes Articles Awards-1980 Foundation Fork Investigation -North Trinity River Photogrammetric Measurements for Land Surveys-Nicolet National Forest Wisconsin Ottawa National Forest Michigan Estimating Project Travel Cost and Mileage An Empirical Evaluation of the Proration Option of Network Program ENGINEERING IN A FORESTRY ENVIRONMENT M I N COST United States Department of Agriculture Service Engineering Technical Engineering Staff pp5i St April Field Notes Forest Washington Volume Number Engineering D.C. System Information R.K UýS PROFESSIONAL DEVELOPMENT DATA MANAGEMENT RETRIEVAL contained Information developed in guidance for of FIELD NOTES has publication this employees the United of TECHNICAL been States De-partment Forest Service its contractors Department of AgricultureThe Federal and State agencies. and its cooperating of or use of interpretation own assumes Agriculture this no for the by other than its responsibility information employees. publica-tion names ap-proval The use is Such trade of for firm or corporation information and convenience the use does not constitute an by the any product be suitable. United or States service official this of the reader. endorsement Department the exclusion to in of of or Agriculture others of may that re-commended instruc-tions The of text in the publication represents or or type of policy this in by the technicians publication procedures approved except material engineering the personal opinions author and must not be construed the respective is FSM publication should not intended mandatory Because references. all read each exclusively engineers issue for as of the and however engineers. REPORTS 13 4 1981 US SEgyý fOR15T ENrOF TO READERS OF INVITATION NOTES FIELD Every reader article is author a potential would you like to an article for Field Notes. of share with Service we engineers If you have a news you to invite send item or short publication for it Field Notes. the.respec-tive informa-tive in Material submitted to the Washington Office for publication should be reviewed Regional Office to see that the information and of interest may vary from items are news to and sentences short All preferred. double-spaced Service Engineers Forest several is ideally 7113. to be submitted material however short articles Office should drawings original by accurate of length the Washington should illustrations The typewritten pages submitted material all FSM several to current timely technically or be typed glossy prints or negatives. Field Notes Area Headquarters from the number increase from the Field personnel their Regional the Washington Forests and Forest ask your Office Manager list to distributed is Washington of or Service the Regional copies sent to Office directly retirees. If you to are Copies of Regional Data Engineering Technical your office. all not currently back Station Systems issues are Coordinator also available Office. should submit material for publication or questions concerning Field Notes Melvin R-4 Ted Wood R-9 Mujeebul R-2 Mike Clinton R-5 Paul Stutes R-10 R-3 Juan Gomez Bo McCoy R-6 Kjell Bakke R-8 Tom problems to Coordinators R-1 Coordinators and on the mailing Dittmer should direct questions WO concerning format editing Service-USDA Engineering Staff Attn Gordon P.O. L. RP-E Rome Bldg Editor Box 2417 Washington Telephone D.C. Colley Vanderpool to Forest Al Hasan 20013 Area Code 703 235-8198 publishing dates and other l FIELD NOTES AWARDS ARTICLES - 1980 for the Field Notes articles The rating from readers was most encouraging. is complete and the response that reflects the rating by a point value The articles were assigned first - 3 points second 2 points third - 1 point. the readers to The total number of points earned by each article was calculated determine the ranking given below. AUTHORS TITLE RANK Bath 1 Solar 2 Practical Toilet Solar Facilities Thomas Smith William A. Speer James Applications -Wilderness Boundaries Describing in Some Comments on Methods General Use One Land Surveyors 3 C. C. M. Kocer Doak R-8 R-3 R-3 Viewpoint Congratulations the papers are to the winners Checks will be forwarded as soon as processed. to the authors who The thanks of all Field Notes readers are extended and slim took the time to write articles in spite of heavy workloads the cooperation of the readers who submitted We appreciate staffing. efforts are of thereby demonstrating that the authors rating sheets value to the field. arti-cle of the way the year submit YOUR are already one-third through for 1981. Tell other engineers for the Field Notes Articles Awards a difficult how you accomplished job or found abetter way of handling and valuable a particular was interesting a problem or why experience to YOU. We Send your article to - USDA FOREST SERVICE Engineering Staff Attn G. L. Rome Editor P.O. Box 2417 20013 Washington D.C. Rm. 1112 RP/E 1 SOME OBSERVATIONS RECENT FIELD on NOTES VOTING non-A rela-by construc-A or Stuffing or or the Ballot Box Shades of Old Tammany The Carpet-Baggers Hall Return A WO protagonist of proper presentation of written communications was designated to perform a perfunctory perusal of the ballots received from parochial evaluators of the articles submitted for Field Notes in 1980. peculiar possibility was posed the preliminary observations penury of either personal pride or professional position on the part of the correspondent. the conclusions However of the review secondary the supported iteration of a strong previous excitation olfactory Danish that emanated from in the correspondents tionships that were caligraphy identified in the tion of the ordinal indicators of selection. a pedan-on Bevel-ed to wit pervasive and perhaps pernicious situation was identified in which singular similarities in ciphers and concentrated selection superimposed the secondary reproduction medium utilized for the communication seem- to signal a repetitious reporting of preference by a certain single reader no connotations of marital status intended. specific-ally We wish to avoid assuming a tic position or pontificating on the problem ad infinitum or oping petulant that respondents resent the detailed inspection of the submittals. But we also hope to preclude future tion of the actual reflection of the readers factors. response obfusca-Presuming select-record a potential for misof the implicainterpretation tions derived from the graphic review was a secondary made by peers of the correspondent concerned and by management read-levels thereby precluding dethat might be as derogatory or denoting inter-preted ductions 2 the ballots for ... Ergo ing the most beneficial articles in the Field Notes in 1981 will and dated by the be signed ers submitting them. ---The Editor FOUNDATION INVESTIGATION NORTH TRINITY Alex FORK RIVER Tary Region solution most practical to be appeared the use of a Caterpillar 966C front-end loader with logloading forks that was available for rental from a logging firm in the vicinity. The 966C loader when adapted afforded an ideal working platform for the drill rig furnished by Forest R-6. the Umpqua National 5 Geologist Shasta-Trinity NF of the North The foundation investigation Fork of the Trinity River Weir entailed the thickness of drilling to ascertain the alluvium in the channel and the depth of the bedrock upon which the proposed structure could be erected. It should be noted that bedrock are outcrops of the stream present on both banks to adapt the loader to the task platform was built on the bottom forks from 2- by 12- and 2- by 4-foot lumber to provide the working area for the drill and the driller. Two heavy-duty garbage cans or two 55-gallon drums depending on stream depth were tied to the bottom of the logloading forks for stability. Additionally this modification served to slow or prevent the bleed-down of the loader hydraulic system and the eventual of the drilling platform. sinking Figure 1 is a photograph of the 966C loader with the small drilling rig mounted on the forks. In order a One major impediment existed Excessive in an turbidity could be introduced active fishery by the task of getting the drill rig into the stream and moving it from drill hole to drill hole. After consultation with the California Department of Fish and Game and the California Water Quality Control Board it was decided that entry into the stream with investigative equipment was justified. comment was expressed about An anonymous the setup It sure looks like Mickey Mouse. Reply It worked -- and nicely at that. Several solutions were considered to minimize turbidity including the construction of a gravel berm to serve as and a drilling platform. The cleanest ý4 ý bF Figure 1. 966C Loader with Drilling Rig 3 meas-Land PHOTOGRAMMETRIC MEASUREMENTS FOR LAND SURVEYS NICOLET NATIONAL WISCONSIN FOREST OTTAWA NATIONAL MICHIGAN FOREST Na.-ing Victor H. Hedman Region 9 Surveyor In a discussion of photogrammetric urements for land surveys there will be a question as to the attainable degree of accuracy and the tolerance error allowable. Is a positional of accuracy 1.5 feet or a relative accuracy of 1 part in 3000 and supportable ble for the rural land surveys of tional Forest boundaries With the advent of electronic distance ments accuracies than those greater made with photogrammetric measurements and this factor are easily attainable is reflected in standards of accuracy quired in many of the States however it must be recognized that these ments are urban-oriented. The need for urban accuracies is not evident for tional Forest lands nor is there any known court case that has challenged photogrammetric measurements when proven photogrammetric techniques have been applied. defensi-ated measure-to require-that Na-changing re-has INTRODUCTION In FY 1958 the line program was initifor locating marking and maintainthe boundaries of lands administered and managed Prior by the Forest Service. that time little had been done to maintain and perpetuate the corners and lines as established by the public land survey system since then the emphasis been on the recovery restoration and establishment of corner positions control the locations of National Forest boundaries. With the emphasis to boundary line locations and marking the use of photogrammetric measurements for locating the boundary line between corner positions controlling is one of the techniques that is being considered and tested. PHOTOGRAMMETRIC MEASUREMENTS the Forest Service In 1958 Eastern Region used photogrammetric measurements as a pilot test project in the retracement and corner restoration of a survey to in Missouri. The project township if photogrammetric measurements could be applied to land surveys within acceptable limits of accuracy was undertaken in cooperation with the Washington Office and Phelps County Missouri. The work included the establishment of section subdivisional corners and the retracement and recovery of existing corners. The results were marginal to techniques and equipment compared now available for such projects. and equipment have improved Techniques since 1958 and further improvement can be expected however increased costs of the limits of tolerance narrowing may not be economically justified if present limits serve our needs. The accuracy of photogrammetric measurements will improve but it is not evident that such ments will match electronic measurements. is one of the tools of Photogrammetry measurement that has a significant place in land surveying and related fields and the results of tests and limitations of photogrammetric projects on the Nicolet and Ottawa Forests are pertinent. measure-determine con-metric knowl-projects. Several before photogramyears elapsed measurements were started and on the Chequamegon and Ottawa completed National Forests for smaller two-section In recent years larger 8and 16-section projects were started and completed on the Superior National Forest none of these was done with the of locating and marking the boundary line and only corners were recovered restored established and monumented. Using aerotriangulation coordinates for these corner positions the proven measurement accuracies on projects ranged from less than 1 foot in horizontal to a position of 3 feet in position marginal tolerance the majority of the tests for accuracy of corner placement were within 1.5 feet position when checked by closed ground PHOTOGRAMMETRIC TEST PROJECTS Error in photogrammetric measurement may result from several sources ground trol accuracies quality and scale of aerial photographs type of equipment used and the level of skill and edge of project personnel. posi-purpose The aerial is controlled photograph by coordinate targets of known tions and it is further rectified for the tip and tilt and drift of the plane as each frame is exposed in flight. Bridging techniques by stereoplotter are used to tie photographs The together. small discrepancies in matching ping photographs to known points common to adjoining photographs are known as residuals inherent errors that require tolerance if photogrammetric acceptance measurements are to be used. The uals cannot be reduced to zero by sently known and equipment. techniques ground overlap-these pre-traverse. resid-of 5 Nicolet National vari-ance Forest are within is foot 1 2.1 of this section was done photography flying a single north-south strip at The a photo scale of 1 inch to 800 feet. residuals and positional differences derived by the reading of eleven common photographs are points on overlapping Note that seven of shown in figure 3. the eleven differences were positional between 0.6 to 0.9 foot which does not for errors in field allow much tolerance measurements if the positional accuracy by requirement is 2585.5 o 2586.2 N1/16 N foot. 1 2573.6 2572.6 NW rn the maximum The In Forest County Wisconsin a section was subdivided measby photogrammetric urements using controlled ground targets near were placed figure 1. Targets lines that were to be lothe boundary cated and marked and the photogrammetric measurements from target to boundary line the field control lowere compared with cation of the same lines figure 2. The variance in photo measurements subject residuals of photo to the inherent show that half the measurements bridging 1 and feet. CN1/16 N N 1346.3 1346.4 2598.9 ý o 2598.9 CE1/16 LO N lf MM 2727.4 2728.7 CS1/16 S1/16 2764.9 2620.3 2620.5 SW S1/16 2764.1 S1/4 104.0 103.8 S1/4 -ýE-ýc2620.5 - 2620.3 - - by Figure aerotriangulation 1.--Photogrammetric Forest 6 IO line targets by field measurement County o9 coordinates Measurements Wisconsin. of Section 20 T34N R14E 4th P.M. Photo Field Line N N CE CS 1/16th-CN 1/16th 1/16th-North 1/16th-S 1/16th 1/16th Figure Residuals 17.0 16.2 1/16th-NW SW-S Control Control feet 16.3 West 0.50 0.63 0.80 -0.73 0.34 0.81 feet Feet 0.7 1.2 3.6 1.7 1.9 39.7 89.8 40.8 1.1 91.0 1.2 75.1 73.0 2.1 20.3 21.1 28.8 30.0 0.8 1.2 27.3 27.3 0.0 7.1 7.2 0.1 35.3 35.9 0.6 38.3 38.6 0.3 7.0 6.4 0.6 Difference East in 15.0 2.--Comparison of photogrammetric field control locations. Positional Variance Feet measurements with photo-graphy Using 1 inch to 500 feet we attained results comparable to those attained by using 1 inch to 800 feet on the Nicolet project. racy. test was made to determine A second whether field control could be held to could we the absolute minimum that is obtain results from offset accurate line by knowing target to the boundary only the distance between two corner positions on the Y ling targeted axis or must we have known distances corner positions between on targeted both the X and Y axes of the stereomodel control--0.44 0.71 0.03 0.71 1.03 0.41 1.11 -0.46 0.91 -0.85 0.20 0.89 1.02 0.87 -0.21 0.91 -1.97 0.56 0.63 -0.28 0.47 -1.04 0.41 2.02 0.76 0.63 1.14 In a distance of 1 mile between two on the Y axis targeted corner positions the error from six offset targets to the straight line between corners ranged As soon as we controlled up to 5 feet. the X axis the variance dropped to 1.8 feet as the maximum difference. viously there are no short cuts in and procedures to obtain principles liable results. Ob-Testing re-photography Figure Ottawa We 3.--Residuals National and positional differences. Forest can push limits and principles. scale needed to determine if larger accuwould provide greater 7 CONCLUSIONS land survey Photogrammetric projects have standards met FS Regional for accuracy 1 part in 3000 1.5 foot positional These accuracies will not accuracy. meet some States requirements accuracy however the latter are urban-oriented the conveyance of lands in --involving urban areas. We are not aware of any court cases that challenge photogrammetric measurements for land survey. The Ottawa test proved we could not take any short cuts in establishing ground control for photogrammetric measurements from target to boundary line. 8 The Nicolet test project and other cited projects prove that we can meet 1.5 foot accuracies for restoring or positional corner positions when establishing using properly-spaced ground control and proper and equipment. photogrammetric techniques there are limits on the use of However line offset a boundary targets to locate the FSM required of 1 foot. to accuracy The several completed projects indicate would allow use that a 2-foot tolerance of photogrammetric measurements and the be relaxed if FSM requirements should measurements are to be photogrammetric used in locating the boundary line. ESTIMATING PROJECT COST AND MILEAGE TRAVEL John P. Haynes Robert Harding Civil Engineers Region AM 3 M - Mwc head-INTRODUCTION T total travel costs the Ranger Station out working or other of quarters. With the high cost of fuel and mileage to have torn targets it was a mistake down those remote work centers. This statement was overheard recently and may or may not have been valid. The work centers in question were in poor repair and were the required deemed not worth under the pollution abateexpenditures ment program. The proper question is and Considering energy conservation personnel ceilings where are work centers justified Something more than intuition is needed this to answer d-2t T c rt2 C total travel costs of a work center. 2rt1 J 2m AT re-lating t3W d d question. work center needs the help determine following expressions were derived hours work project work travel schedules labor costs per diem rate and vehicle costs. The total costs are the sum of personnel costs for travel time the vehicle costs and the per diem costs. These formulas can be used to travel time miles compare personnel and costs for various work center alternatives or various work hour schedules. out working W-2t1-2Wt3 11 1 C ANALYSIS ml2 2 T 3 W WS d1 d - Twc To P total travel time in person-hours out of the Ranger Station working or other headquarters. 2Jt total travel time in person-hours out of the work center. 2Jt1 AP P - Project work r Average labor W Length field d 1 t3 working W-2t t J t2 2 d-2t2 Pwc Where 1 P t3W/d -2Wt d 3 person-hours $/hour costs of workweek or stay Length of work day hours Travel time HQ to WC Travel time HQ to project hours Travel time WC to project hours miles hours in hours 11 Distance HQ to WC 12 Distance HQ to project miles 13 Distance WC to miles C Crew m Vehicle S Subsistence wc Size persons project in one mileage vehicle cost $/mile person-Mwc M Total miles Total miles Travel w/o W.C. in 2J12 Cd-2t2 Travel 2J11 w/W.C. in 13W/d1/t J $/day Project Work is the number of hours of work needed or planned on Travel time is not included. site. CW-2t1-2Wt3 d 9 r labor costs is the total Average charge for salaries for appropriation the crew per hour divided by the number of people on the crew. This must be for work schedules that require overtime payments. ad-justed cost of using weigh against work center. the work center should not the justification of the Hewlett-work cal-worked Instructions Program The or stay in field length of workweek describes how long the crew would while at a work center before returning to the headquarters. If the crew a regular 40-hour week while at the work center before returning to the headquarters W would equal 40. If they worked ten 8-hour days with 4 days off W would equal 80. W d The length of work would be 8 for day a normal 8-hour day. Where work schedules call for two different work days such as eight 9-hour days and one 8-hour would be the average day or 8.89 d hours HP-97 These calculations can be easily done on desk top calculators such as the Packard HP-97. The following program was designed for the HP-97 and will culate Pwc AP Mwc AM Twc cards the and AT. Magnetic containing from the authors program are available Region 3 Engineering staff unit. P M T The accompanying Work Center Travel Cost and Mileage Summary Sheet is used to summarize the estimated costs when more than one project is involved. Load the Then enter program into the calculator. the values for variables P through S into storage registers 0 C. through Press the button A to activate the The estimated travel time miles and costs will be printed. pro-gram. possi-used sched-on C The crew size refers to the average number of people riding in a vehicle. Where the crew rides in one vehicle C the number of people on the would equal crew. Where more than one vehicle is C would equal the number of people the crew divided by the number of vehicles m The vehicle mileage cost is the total cost including F.O.R. or other monthly costs plus the mileage The charge. monthly charge must be prorated to the miles driven. Where estimated monthly more than one vehicle is used will cost per mile. equal the average vehicle m When justifying the construction of or the retention of a work center compare the annual cost of the work center with the total travel cost savings when using Do not add in the the work center. results for projects which will not save If the work money using the work center. center is used for these projects it be to save miles. The additional Before the calculations for an accepting individual project explore other ble project variables such as work ules and crew sizes. Simply enter the variables into the appropriate changed and press button AQ storage registers Enter on the work sheet the results for the project plan most likely to be used. for each project the procedure Repeat the results on the work summarizing sheet. step-by-step assist the estimator an illustrative example is shown along with the of using the program. procedure To stor-wil 10 Steps 1. according 2. age Load program into calculator to H-P instructions. Key project variables into one project at a time. registers Variable Sto Project Reg Project 1 1000 800 r 1 7 7 7 $/hr. W 2 40 80 40 hrs. d 3 8 10 10 hrs. tl 4 .7 .7 .7 hrs. t2 5 1.00 1.00 1.50 hrs. t3 6 . .2 .5 hrs. 11 7 15 15 15 miles 8 20 20 30 miles 13 9 10 5 10 miles C A 3 3 3 m B .5 .5 .5 $/mile S C 16 16 16 $/mile HAPPY Headquarters Center CREEK Work ýtzaTECT oSEGT Values Time rave M AP WC erson/hrs erson/hrs miles mi R.-ARDW6 by Date VJC.. personP/hrs Projects people/vehicles Done BUFFALO ZuN Location Center 600 2TD Travel 3. p-hrs. 0 Example 2. 3 J 12 Work Project 2 I\ Miles c es .efi $p Travel Costs ý dollars miles 2 250 74 176 I 667 41RZ 1174 583 3 257 qi 161 174 638 1D77 2 657 1130 2251 52110 w dollears AT dollars 24181 I oZ 556 2101 6. 7. 8. TOTALS of Cost Projects Worked Work Center. Effective Out of 567 COMMENTS Fozz-Ec-F IIUoRK1/JG BUM1\IATEO AND W ILL FROM BE 337 170 Our GO I Coný6rl JJo2KED Ta OF 2i.iJTE2 12K- FREkrQUART CENTER EFEECýRuF- COST- Cosr3AVINCxs THUS OF I-r \Ab9K WAS ý-p-m1TeR_ I I7zosEC 2 oýýcx 3 WC TRAVEL S8 4.582 5 týzasEC.r uQ WORK .o Ts TIETOTAL.T1AF-AILEA1EiANI R1 OUT- W0 3381 COST MILEAGE SUMMARY SHEET 11 Exanrple Q Optional 3. Press RRG PRINT and accuracy of varithe storage registers. to check contents ables keyed into 1 Project - Storage Value Register Sto 4. print Printout Actual 600.00 W_ 7.00 40.00 8.00 d tl t2 t3 11 2 13 C M PROGRAM Program Ste 267. 0 T -63 00 003 RCLO 36 004 RCL5 36 21 x RCL3 36 007 2 1 2 M 3 0.75 4 1.00 5 0.50 15.00 20.00 6 10.00 9 3.00 A 0.50 16.00 B 0.00 D 0.00 0.00 E RCL5 36 - 011 2756. 8 -759. Twc AT C I 5. 033 034 -45 - STOE 35 035 068 Repeat steps 2-4 for each 103 RCL2 36 104 RCL3 36 00 CHS -22 071 RCL8 36 08 105 05 038 RCLD 36 12 106 -35 107 03 039 040 072 073 RCLB -35 041 16-11 074 075 RCLA 02 RCLD RCL5 36 14 076 RCLI 36 01 110 36 05 077 078 RCL5 36 05 111 042 36 14 -55 PRIX SPC -14 05 043 -45 044 -24 045 STOD 35 -14 046 RCL8 36 -24 14 36 02 048 015 RCL3 36 03 049 -24 050 PRTX 06 051 STOI -14 35 46 -35 052 RCL2 36 053 RCL3 36 RCL4 36 04 -55 021 RCLO 022 x 023 RCL2 024 36 36 2 RCL4 36 RCL9 056 057 x -24 058 059 04 060 -45 028 RCL2 36 02 062 029 RCL6 36 06 063 -35 36 061 RCL7 RCLO 36 36 36 RCLA 36 RCLD 36 -35 112 -55 113 RCLI 36 RCLO 14 114 x -35 115 RCLE -14 116 35 46 117 PRTX 36 02 118 CHS 085 086 RCLC 36 13 119 RCLI -35 120 087 RCL3 09 089 36 2 x 090 01 36 -55 00 -35 RCL2 088 04 -35 STOI 03 36 x 084 x 06 -55 083 02 x RCL4 109 PRTX 36 15 -24 -14 -22 36 46 -55 03 121 PRTX 02 122 SPC 16-11 -14 -35 123 124 SPC SPC 16-11 -24 SPC 16-11 16-11 091 RCL2 36 02 125 -55 092 RCL9 36 09 126 00 093 094 -35 STOD 03 127 128 STOE 35 15 -24 129 STOI 35 46 07 130 DSF2 07 15 096 11 097 098 03 065 PRIX -14 -24 066 CHS -22 x RCL3 36 095 -24 -24 064 x 108 03 -35 082 -35 x RCLE 11 -24 36 x 11 -35 36 36 RCL6 081 -24 055 02 36 08 079 080 x 02 -24 -35 -24 00 - x RCLA 054 027 RCL3 x -35 02 025 -14 -24 -55 102 16-11 RCL2 020 101 PRTX SPC 014 x 46 -55 069 070 047 36 36 -24 -14 14 RCL6 RCLI PRTX 35 016 067 15 PRTX 030 dollars 3514. T STOD 026 743. 7 012 019 miles 1035. QMwc 013 018 1778. M 036 037 11 -24 008 017 111. Code DSPO 010 hours 155. Key Function LBLA 009 1 LISTING 002 006 Project will project. 001 005 12 of Example AP S 032 Printout Pwc r calculator P Re J 031 Press button out costs. 099 100 RCL7 36 -55 RCLB 36 x RCLA 36 131 0 R 00 35 -63 14 02 -31 12 132 RTN 24 -35 133 R/S 51 11 CONCLUSIONS Since developing these formulas it became evident that a major use of the program will be for project planning. Whether or not a work center exists travel time miles and costs can be estimated for alternatives such as different work schedules and crew sizes or for using the work center or not using the work center Personnel and mileage ceilings constraints are becoming more important considerations and may justify using an center or building a new existing work favor-able. one even where are not economics This program allows quick analysis so that the trade-offs can be considered This program was designed to cost of working out of a work the cost of working out of a such as the Ranger Station. where crews are stationed at the compare center with headquarters However the work costs can be compared for using different work centers by considering one work center as the headquarters and the other as the work center. Travel time from HQ to WC and distance from HQ to WC would then be entered centers as 0. 11 t1 13 AN EMPIRICAL EVALUATION OF THE PRORATION OPTION OF MINCOST NETWORK PROGRAM mainte-Management Peter Sciences U.S. Variable cost nance cost. Wong Forest Berkeley Staff cost hauling Equation Service Step Calif. Iteration 2. Iteration 1 1 is greater than 10 go to variable cost on each Recompute to the link for each sale according formula following If mainte-more construc-as INTRODUCTION iteration step The MINCOST Program has been used frein recent years by transportation quently for network in place of analysts analyses sophisticated computer models such the Timber Transport Model Transand the Integrated shipment Model Model. Resource MINCOST appeals Planning to users mainly because of simplicity in data input and insignificant computer run costs. When the problem is to obtain the best network and where best is usually defined in terms of minimum total cost the proration option is most often chosen. 5. 1 Variable cost hauling cost nance cost Equation reconstruction tion cost cost/traffic flow traffic volume on the link from last iteration if it is than 0 greater or current timber sale volume otherwise vari-the where traffic The purpose of this paper is twofold. the heuristic algorithm used by proration since option is documented few users if any are familiar with the algorithm. the characteristics Second of the algorithm are studied a through series of small hypothetical examples. Generate a minimum path for each Step 3. timber sale on the basis of the new able cost for the links. First PRORATION Step 1. Step 4. Is the traffic volume from all timber sales on each link of the network for the current iteration to that equal iteration If yes of the previous go to ALGORITHM The heuristic algorithm of option is described below. Iteration 5. If Step 5. Terminate step 2. algorithm. Legend 1 100 100 the Sale 1 22 to small numerical example below how the algorithm works. The schematic network is shown in Figure 1. For simplicity all links are 1 mile in and with hauling cost of $10/mi/ length timber unit. The construction costs for links 1 3 and 2 3 are $1000 and $10000 respectively. h10 2 go The For each timber sale generate a minimum cost path to a market through a mill on the basis of the following variable cost for each of the network links. Sale No. no step illus-trates the proration 1 100 flow No. units of timber network node at enter 2. 1 2 h10 c10000 h10 c1000 h Mill Figure 1. Market Schematic c hauling cost construction $/mi/timber cost in $ in unit. Network 15 h10 2 Minimum paths for the two Iteration 1. sales are generated using hauling cost shown in Figure 1. The solution is shown in Figure 2. \100 1/ h10 h10 O Legend 100 means 100 timber is the link. Figure 1. $10 of this $1000/1 iteration 1 2 101 $1010. is Iteration of hauled along h10 cost on each Iteration 2. The hauling link is recomputed using equation 1 3 will have the For example link new hauling cost. following cost Hauling The solution in Figure 3. 2. units h1010 h110 shown - 3 Figure However 3. Since there was no timber Iteration -o-3 and the hauling over link timber sales volumes are different for the two sales the hauling cost used here would not be the same for both sales. For sale No. the hauling cost for 1 is 3 1 as cost Hauling a $1000/1 $10 Sale No. -ý-- b O 2 is Iteration h1010 1 $20 mini-mum Sale No. c 2 h10 100 O 100 h109 4a Traffic b. Flow 4. Iteration h20 Pattern 3 O 1 -ý 2 100 f 100 f O O 3 16 3 for the sales are paths and The flow pattern a traffic paths generate shown in Figure 4c. O Figure 1 $1000/100 1 h109 2 for cost $10 The minimum cost shown in Figure $1010 1 the hauling No. cost Hauling follows h10 2 for sale 3. h10 o Iteration 4. We again recompute the costs on the links using equahauling tion and then generate minimum cost The result of this iteration is paths. shown in Figure 5. o 100 1 101 h10010 h20 3 Figure 5. Iteration 4 algo-are Iteration 5. As in iteration 3 the cost used here for link 2 3 hauling would depend on the sale under study. The minimum cost paths for this iteration shown in Figure and The 6a a Sale No. 4 b. b 1 traffic flow pattern is shown resulting in Figure 6c. Since the traffic on each link for this iteration is the same in iteration as the heuristic rithm terminates. Sale No. h10 c 2 Flow Pattern h10 100 100 100/ l h10010 Traffic h19.9 h110 O O Figure 101 h19.9 6. Iteration 3 5 17 Omile EMPIRICAL EVALUATION 10 of the proration heuristic studied algorithm by means of a series of small hypothetical problems. The behavior 10. is Problem 1. The triangular network shown All links are 1 in Figure 7 is used. in length. O of the solution is The traffic pattern shown in Figure 7. The solution value is $220. The optimal solution is for timber sales to use paths 1 2 3 and 2 3 The optimal solution value is $180. In this case the MINCOST value is 40/180 x 100 22% higher than the optimum. 10 h1 thesoluIn trying to force select the path 1 2 3 in 1 we increased the construction problem cost on each link by 10 times. However the solution traffic pattern remained 1. The deviation the same as in problem of this solution from the optimum is 2. x 100 h1 Problem 7. 1 10 to $2020-$1530/$1530 c100 3 Figure tion p 10 c100 solu-tion Problem h1 c50 10 c500 O h1 2 32%. that A review of the algorithm indicates the solution is insensitive to the construction cost assigned to link The MINCOST solution for a case where no construction cost is assigned to link is shown in Figure 8. The shown in Figure 8 is x 100 96% higher than the optimum. D2 Q-2 solu-tion $2020-$1030/$1030 10 10 c1000 c1000 h1 h1 3 Figure Problem 8. 2 10 Problem 3. The triangular network is used again but with construction costs in such a wa that would make assigned the path 1 2 3 more attractive 1. The solution of this than in problem is shown in Figure 9. This soluproblem tion is $1520-$1030/$1030 x 100 than the optimum. 48% higher 10 c500 O c1000 h1 10 10 c500 h1 h1 O Figure 18 9. Problem 3 $4060-$3100/$3100 from 4. A network constructed is used to detertwo triangles stacking of mine if the solution traffic pattern in a more comearlier problems persists The network and the MINCOST plex network. solution are shown in Figure 10. The value is $4060 which is MINCOST solution Problem x 100 31% higher than the optimum. The traffic remained the same when the timber pattern sale volumes at nodes 5 and 6 were to 5 units. We can see that the changed traffic pattern here follows those of 1 problems through 3. 10 10 c500 W 5 6 10 c1000 W 10 10 / c1000 h1 c500 h1 2 10 c1000 h1 c1000 // 30ý 0 h1 3 Figure 10. Problem 4 19 100 1 Problem 5. A network similar to the one 1 is used here except used in problem that flow between nodes 1 and 2 is perThe solumitted in either direction. is shown in Figure tion for this problem 11. The MINCOST solution value of $2020 solution. coincides with the optimal h10 c0 _ý lO 2 10 h10 h10 c10000 c1000 3 Figure The timber sales volumes of Problem 6. the 5 are revised to investigate problem to timber volumes. of MINCOST sensitivity The MINCOST solution and the network used MINCOST obtained are shown in Figure 12. solution value of $110020. the optimal Problem 11. 5 0000 1 h10 c0 2 10001 ý h10 c10000 h10 c1000 3 Figure The network shown in Figure Problem 7. would 13 is used to test whether MINCOST of paths to permit select a combination link by both sharing of a construction The MINCOST solution of timber sales. to the optimal $10000 corresponds solution. 12. Problem 6 100 100 O h10 c2000 h10 c2000 2 h10 c2000 h10 c10000 h10 c10000 200 O Figure 20 13. Problem 7 Problem 8. The network shown in the 1 MINCOST Users Guide is employed Region of MINCOST on a to check the performance The slightly more realistic network. network characteristics are summarized in Table 1 below CONCLUSIONS con-3 the the preceding examples we can see MINCOST solution may be the It is not optimum or very far from it. obvious for what network characteristics or a bad we can expect a good solution one. More empirical evaluation of MINCOST using larger and more realistic is Forest Service network problems A theoretical way. analysis of the heuristic algorithm and proration of MINCOST with other available parison will be network analysis procedures ducted in the near future. From that under-which com-solution The MINCOST solution is shown in Figure value is $511872. The Its solution solution is shown in Figure optimal 15 has a solution value of $506944. Therefore for this problem the MINCOST is within 1% of the optimum. for replacing link Note that except D-Lo-7 4 in the optimal soluby tion the remaining networks are the same for the two solutions. 14. It is clear from the examples that until more is known about the quality of the the solution produced by MINCOST solution should not be accepted blindly. ---1 ---2 ---3 ---4 ---5 ---7 ---8 ---9 ---10 Table Link ID Node Node Length Mile 1.--Network $ Characteristics Haul Forward 1 2 4.7 38200 --- 1 4 8.2 68400 1.31 5 3.8 61300 0.91 3 4.2 27800 --- 4 3.6 50000 0.91 4 4.1 32500 0.91 7 4.9 72700 0.71 5 5.0 50000 0.91 0.51 2 6 6.2 --- 6 2.0 32500 0.71 8 6.2 --- 0.51 6 7 2.5 50000 0.91 6 8 7.1 28000 0.51 8 8.2 --- 0.41 10 11.7 --- 0.51 8.7 --- 0.31 10 28.2 --- 0.41 11 16.7 --- 0.31 11 0.0 --- 0.0 4 9 8 Cost Construction Cost Per Mile Backward $ 1.31 1.31 0.91 0.51 ---21 10200 10200 4800 6200 6200 sale sale sale 2 sale 4800 sale 2 --ý-C sale 3 O O Ný . 1 0 N 3 O C T / 6 Ný - 4 102 00 5 CO Ch r i 4 5 C1 ý ci 7 6 16400 i CO -1 7 6 8 8 .QO 00 ý ar mill 0 10 qpp 9 mill milli Network Not 22 to mil 1 market 21200 Schematic 9 11 market 14. 03 ý0 11 Figure 10 Layout of Big Creek Solution and MINCOST 21200 Figure Schematic 15. Scale U. S. Network Layout of Big Creek and Optimal Solution Not Scale to GOVERNMENT PRINTING OFFICE 1981 340-938/314 REST SERvq U S ENTOrA61ET. TECH INFORMATION J6.TEM Volume 13 Number 4 April 1981 Engineering Field Notes