(DTM) OFFICE OF DESIGN ENGLISH PRELIMINARY SURVEY SPECIFICATIONS

August, 2008 (DTM) OFFICE OF DESIGN ENGLISH PRELIMINARY SURVEY SPECIFICATIONS A. GENERAL These specifications describe the collection of preliminary field survey data. This data must be sufficiently detailed to enable the design of a highway project. The collection process shall therefore include, but not be limited to: Setting control monuments GPS observations of Horizontal control Completing a transit line (Baseline survey) relative to the GPS control Running bench levels Obtaining surface elevations at spot locations & with break lines Making reference ties to supplemental control points and control monuments (GPS monuments) Preparing property ownership plats along the corridor Determining utility location and ownership Creation of a project index The collection process shall also include the preparation of any special data needed for bridges and culverts, such as: Preliminary bridge and culvert sheets [Iowa Department of Transportation ( I.D.O.T.) Form Nos. 621001 and 621004] Stationing-U.S. Survey foot definition If the Survey is in U.S. Survey foot units, the stationing will be based on the one-hundred foot station (1 sta=100feet) A station equation that relates the U.S. Survey foot Stationing of the survey to the U.S. Survey foot stationing of the as-built highway plans will be placed at the project (BOP) and the project (EOP). The format for all Station Equations (relating to an U.S. Survey foot plan) will be as follows: P.O.T. Sta 492+00.00(E) This Survey= P.O.T. Sta 492+00.0(E) As Built Plans, followed by the plan project number. Note: If the existing U.S. Survey foot station at the (BOP) is less than 30+00 and does not allow for additional survey back of the (BOP), the survey crew will set an arbitrary station value large enough to prevent possible negative stationing on a project. Survey stationing shall normally progress from south to north or from west to east. Occasionally the as-built plans will include stationing in reverse of the norm: ie: increase from north to south or from east to west. If that situation should arise, please contact the Office of Design. 1

Project Control Requirements A control network will be set and observed using survey quality Global Positioning and proposed methods preapproved by the Survey Manager of Office of Surveys or a licensed land surveyor who is an employee of the Iowa Department of Transportation. The methods may include but not be limited to use of Online Positioning User Service (OPUS), high accuracy county control and/or HARN control or the Iowa RTN. The network control points will be spaced such that they are inter-visible both ahead and back along the proposed corridor. The frequency of points will vary from a few hundred feet to 1.4 miles depending on the terrain of the project. The U.S. Survey foot values of the control points in a network will be furnished using the following conversion. Iowa North Zone: The metric value of the local project plane coordinate multiplied by 3.280833333. Iowa South Zone: The metric value of the local project plane coordinate multiplied by 3.280833333. The following G.P.S. Network information will be available: The final project control coordinates in an electronic ASCII format A copy of an aerial photo with point locations spotted on them A text file describing the point, the milemark value and the approx. highway as-built station value (when applicable) Final Project Report Misc. project files All project control furnished by the department will be held fixed while collecting field planning DTM data. If RTK G.P.S. is used, methods pre-approved by the Survey Manager of Office of Surveys or a licensed land surveyor who is an employee of the Iowa Department of Transportation will be adopted. The Department will provide a SAP (Survey and Photogrammetry) number to be used within the Departments file naming convention to name electronic field survey files associated with the Planning DTM data. Survey stationing shall normally progress from south to north or from west to east. The recording of Transit Notes shall be as follows: Rural areas - Electronic Data Collector Urban areas - Electronic Data Collector Field books used for the recording of survey data shall have hard bound covers and include a table of contents of the recorded data. The surveyor shall advise the District Land Surveyor of the survey work prior to beginning work. The Iowa Department of Transportation will provide a survey request aerial. This aerial will define the proposed corridor survey limits. Any proposed modification to the request must be approved by the Office of Survey. 2

B. EDM EQUIPMENT REQUIREMENTS Distances shall be measured using a modern electronic measuring device with manufacturer's accuracy specifications of + 5 mm + 5 ppm or better. Angular measurements shall be made using instruments with manufacturer's accuracy specifications of 6 seconds or better. The consultant shall furnish all monuments, stakes, pins, spikes and other incidental supplies. C. GLOBAL POSITIONING EQUIPMENT REQUIREMENTS Equipment used must be specified by the manufacturer to be capable of 2cm or less horizontal and vertical accuracy. Dual Frequency receivers are advised. D. LOCATION OF AS-BUILT CONTROL If the survey is within + 500 feet of the existing highway, the surveyor shall make a DILIGENT effort to FIND the AS-BUILT@ P.I. s along the existing highway, as shown on current "AS BUILT" plans. If after a diligent search, the "AS BUILT" P.I.'s cannot be found, the tangent between the P.I.'s shall be located using the P.C. & P.T points or splitting the slab at or near the as-built P.C. and P.T. points. Information recorded in an ASCII file on these As-built P.I.'s and tangent control points shall include: Type of point, either P.I. or tangent control point Point number Station value and distance from the survey baseline Coordinate Value (xc & yc) Station value of a P.I., P.C., P.T., point as found on the as-built plans The format of the ASCII as-built control file report will be as follows: Examples: Control Point #600, Sta 100+00.562, 45.456 left this survey = P.I. Sta 326+25.62 AS-BUILT Plans The yc, xc, and the Radius of the curve Control Point #625, Sta 125+00.562, 105.456 left this survey = P.I. Sta 300+20.52 AS-BUILT Plans The yc, xc, and the Radius of the curve These points will enable easy recreation of the as-built alignment. SURVEY PROCEDURES Control Monuments GPS control monuments 30 inches in length or longer shall be used for proposed permanent control. Monuments should be established in areas that will survive construction of the proposed project when possible. The referencing of permanent control monuments must enable convenient recovery. Reference sketches will be illustrated in the Distance Meter Readings Book or the Transit NoteBook or electronically collected. Additionally, each control monument point shall be referenced to three durable, physical objects (ie: trees, poles, fence posts, etc.) Control Points 3

Iron pins, 15 inches long or longer and 1/2 inch or more in diameter, are to be used to monument supplemental control points along the baseline and on sideroad surveys. These pins are to be buried at least 3 inches deep, except in cultivated fields, where they are to be buried 15 inches deep. When permanent points fall on concrete surfaces, crosses may be chiseled. When permanent points fall on asphalt surfaces, frost nails, PK nails, or other similar nails may be set. The referencing of permanent control points must enable convenient recovery. Permanent control points shall therefore be set no further than 1300 feet apart and shall be intervisible. Reference sketches will be illustrated in the Distance Meter Readings Book or the Transit Note Book or electronically collected. Additionally, each permanent point shall be referenced to at least three durable, physical objects (i.e.: trees, poles, fence posts, etc.) with measurements to the nearest one-hundredth of a foot. A nail in the present pavement used as a reference will not be considered a permanent point, and caution will be taken not to set reference nails in valuable trees. All references shall be included in the G sheets. The coordinates of these points are also in the C control file. Other Procedural Information The approximate location of government section lines and city corporation lines shall be noted when crossed. Name and address of the nearest office shall identify the ownership of all utilities. This utility information will be recorded in the utility legend of a field book. An illustration of ownership must be supplied. Property Ownership Plats A 1" = 300 scale property plat will be created on an aerial paper print. The plat will identify the owners and boundaries of all parcels within the survey limits. An alternate product such as a county GIS print or electronic submission may be substituted with the approval of the Office of Survey. E. TOPOGRAPHY Topography obtained in the field shall locate all features both above ground & underground, which cannot be determined from aerial photography, when photogrammetric techniques are applied. Electronically collected field data must have the appropriate feature code. A list of feature codes will be supplied upon request. Field located features will include: Right-of-way rails Speed limit and milemarker signs Telephone pedestals Septic tanks Utility valves Approximate locations of leach beds Wells Buried telephone cables Gas mains Buried water lines Farm tiles Concrete slabs Buried gas tanks Gas tank Monitoring Wells Advertising Billboards All other underground storage tanks 4

A report (. rpt files) of these objects shall be created and labeled with a point description, feature and the station-plus and right angle distance from the survey baseline. For file naming definitions, see page 10. Culverts shall have a station-plus and right angle distance right or left from the survey baseline to the inside edge of the headwalls (parapets). Entrance pipes shall be located with station-plus and right angle distance right or left to the ends of existing pipes. Side road culverts shall be referenced to side road centerlines, and their distances right or left from the mainline survey baseline shall be noted on the top of the pink culvert sheet (I.D.O.T. Form 621001) (see attachment 2). In all cases, the plus and distance out to a culvert must be to the nearest one-hundredth of a foot, accurate to +.03 feet. The size (length, width and height) and material of all culverts and pipes must also be noted (see example). On all culverts, the drainage area and character of the watershed must be noted, and breaks in the barrel (either horizontal or vertical) must be located. If photogrammetric techniques are not applied, all pertinent topography shall be obtained through field survey. Photogrammetric topographic data shall be compiled and submitted, as specified in the Photogrammetric CADD Mapping Specifications. For all mainline and side road bridges within the survey corridor, the station value at the center of the bridge, the size (length, width) of the bridge, the construction material used, a brief description of the bridge, the drainage area, and the character of the watershed shall be noted. This information is recorded on the Preliminary Bridge Sheet (Form 621004) In urban areas, it will be necessary to note station-plus and right angle distances to the curbs and gutters, the sidewalks, and any buildings abutting the street or survey baseline. Locate both edges of entrance doors and loading docks to commercial buildings. Both the pluses and distances out must be recorded to the nearest onehundredth of a foot. Side Roads A ML/SR, ML/RR, SR/SR, or SR/RR Station-plus to the nearest one-hundredth of a foot shall accurately note side roads and railroads, which intersect the baseline of survey. All intersections shall be equated at survey baselines, and station values shall be assigned by increasing the mainline stationing by 1000, 2000, 3000, etc. at the point of intersection. All side road /mainline tangents will also be equated at intersection points. The type and width of surface, construction material of surface (a/c surf, asphalt, gravel, conc etc.), the width of ROW, and the name of any intersecting road or street shall be noted. F. BENCH LEVELS Benchmarks shall be established on permanent objects at intervals not greater than 1300 feet and at all structure sites (bridges and culverts) near the proposed corridors. If the terrain is rolling, benches shall also be established for every 40 feet of vertical difference. The setting of small spikes in road signs and less stable objects will not be acceptable. Permanent objects are to be used for benchmarks. The following list in order of preference will be used as a guide to determine placement of benches: Found I.H.C. bench on HDWL of RCB culvert Found IDOT bench on HDWL of RCB culvert Found I.H.C., IDOT or (X) on a Bridge Found (X) on HDWL of RCB culvert Cut (X) on a Bridge or on the HDWL of RCB culvert Found a RR Spike in a Power Pole Set a RR, 80d Spike or Larger in a Power Pole Set a 80d Spike or Larger in a Fence Post 5

G.P.S. Feno Monuments, GPS rebar and other supplemental control pins will not be used as vertical benchmarks; however, a random sample (the more the better) of the GPS points should be used as turns and sideshots along the bench runs. Due to the unstable nature of rebar and the questionable quality of the Geoid96 model in portions of Iowa, the vertical estimate derived from the Static G.P.S. Control Network may not meet our vertical needs. The relative differences between the points have been useful as a check along a Bench Level Run. The majority of the culverts in the state are constructed with a brass button usually referred to as IHC or IDOT bench marks. These brass markers are usually on the inlet end of the structure. All bench levels shall be run by the three-wire method and checked by the loop method. Note: A run between two 1st, 2nd, or 3rd order monuments will be considered closed if the closure error specification is meet. All raw bench level data will be furnished to the department in an ASCII for adjustment. The department will adjust the raw data in the SDMS Format and return a calculated file. An accurate description of all benchmarks and ties to Network Control points shall be recorded. The x, y, values of all benchmarks will also be furnished to the department in a control file format. For details see Section F. CREATING a CONTROL FILE. All benches will be numbered sequentially from 500 through 999 (Numeric only). Turn points should not be numbered Bench level runs must check within [.05 X the square root of the circuit s length (in Miles)] and be based on NAVD 88 datum. The difference between the middle wire reading and the top or bottom wire readings must be less than 0.01. The difference between the observed middle wire reading and the computed wire reading must be less than or equal to 0.003. Example: 4.00 3.00 In this example: top difference 1.00, bottom 0.99 (within tolerance) 1.99 The sum of all three readings is 8.99, divide 8.99 by 3, middle reading is 2.997. (Within tolerance) 4.00 3.00 In this example: top difference 1.00, bottom 0.98 (out of tolerance) 2.02 The sum of all three readings is 9.02, divide 9.02 by 3, middle reading is 3.007 (out of tolerance, because the difference between the original middle reading and the computed middle reading, 0.007, exceeds 0.003) Observations Equipment and method of observation to make measurements should adhere to the following requirements: The level should be in good working condition and at least an engineer s compensator (selfaligning) level should be used. A builder s level is not acceptable. All levels should be tested at the beginning of each project, and adjusted if necessary. In addition, any instrument dropped shall be tested before further use. Level adjustments shall be repeated after no more than 20 days of use if project leveling takes longer than 20 days. The level rod should be at least as good as a Philadelphia, Chicago, California rod etc. It should be checked just prior to the work to see that it is adjusted from section to section. The rod should have 6

some device to verify that any sections of the rod that lengthen it are adjusted to the bottom section properly. A plastic telescoping rod or builders rod is not accurate enough to do the job. The bottom of the rod should be kept clean at all times. Vertical Equations at the BOP, at the EOP, at USGS, and at NGS (or USC&GS) Vertical Datum marks along the project shall be included in the vertical datum information in the index file. The vertical equations at the BOP and at the EOP shall equate your survey to any adjoining survey. Adjusting the level and inspecting line of sight.doc Adjusting the level & line of sight (two-peg test) In new levels, the compensator has been adjusted at room temperature, so that the line of sight is horizontal even if the instrument is tilted slightly. This situation changes if the temperature fluctuates by more than ten or fifteen degrees, after a long journey, or if the instrument is subjected to strong vibration. It is then advisable to inspect the line of sight, particularly if more than one target distance is being used. 1. In flat terrain, set up two staffs not more than 33 meters or 100 feet apart. 2. Set up the instrument so that it is equidistant from the two staffs (it is enough to pace out the distance) 3. Read off from both staffs and calculate the height difference (Figure 1 above). Example in feet Staff reading A = 5.549 Staff reading B = 5.404 H = A B = 0.145 Note that the thousandth of a foot reading is interpolated using the foot rod. 4. Set up the instrument about two meter or 6 feet on line with and away from one of the two staffs. In this example A, and take the staff reading at rod A (Figure 2 below). Staff reading A = 5.496 5. Calculate the required reading B. First read sight A, then subtract H (In this example Sight A is lower) Staff reading A = 5.496 - H = 0.145 A H so required reading of B = 5.351 6. Take the staff reading B. If it differs from the required reading by more than.005 foot or 2mm, adjust the line of sight (refer to instruction manual). Remember to adjust ½ the difference between the actual and 7

required reading. 7. Repeat steps 1 through 5 until the specification in step 6 is met. G. DIGITAL TERRAIN MODEL (DTM) DATA Terrain data collected for DTM generation should include 3d line strings along break lines, and spot elevations. Break lines collected in the field should include the following: CL and edge of paved roads, CL of dirt, or gravel roads CL and edge of paved or unpaved entrances or parking lots Curb or center island Back of curb and gutter line Paved or unpaved shoulders Edge of sidewalks CL of river, stream and draw flowlines Top of bank of rivers, streams, and draws Edge of water (lake, pond, stream, river, etc.) Top and toe of dams Other terrain break lines and features which are not visible in the aerial photography Break lines must not cross each other. Shots along the break line should be spaced to define changes along the break line with a maximum spacing of 100 feet. Spot elevations should be taken as needed to identify changes in the terrain. The format for electronic files containing spot shots and break lines should be provided as shown in attachment #8. H. PHOTOGRAMMETRIC CONTROL SURVEYS When applicable, the consultant shall provide the essential ground control survey. Using this survey, the consultant shall then determine the horizontal positions and elevations of all horizontal and vertical control points required for the photogrammetric compilation of planimetric and DTM data. This positioning should be established so that Photogrammetric CADD Mapping Specifications ("Attachment B") are achieved for DTM and planimetric compilation. The necessary horizontal control points shall be established in conjunction with an arbitrary local grid network chosen by the Iowa Department of Transportation. The standards for second-order horizontal control survey 8

(Manual of Photogrammetry, 4th ed.) shall be attained (see page 422, 8.4.1.3, 1:10,000). Vertical control points and the vertical components of full control points should be noted with elevations that are recorded to the nearest one-hundredth of a foot, accurate to ±.03 feet. The consultant shall prepare a control survey report consisting of descriptions, computations, and sketches. Upon completion of the contract, this report and all other material pertaining to the survey will become property of the Iowa Department of Transportation. I. DRAINAGE For streams that have drainage areas of 2 or less, a profile of the streambed must be shot at 100-foot intervals to a distance of 660 feet upstream and downstream from the centerline of survey. All streambed profiles will be measured up or down stream along the centerline of the stream. For an example see attachment 4. The top of the water must be shot at the following locations: The survey baseline Under bridges The tops and bases of dams The tops and bases of rapids 660 feet upstream and downstream These shots must be recorded to the nearest one-hundredth of a foot, accurate to +.03 feet. Low steel or low concrete will be recorded on all bridges within the bounds of the stream profile. For streams with drainage areas of 2 square miles or more, a profile of the streambed must be shot at 100 foot intervals to a distance of 1320 feet upstream and downstream from the centerline of survey. The top of the water must be shot at the following locations: The survey baseline Under bridges The tops and bases of dams The tops and bases of rapids 660 feet upstream and downstream 1320 feet upstream and downstream As with smaller streams, these shots must be recorded to the nearest one-hundredth of a foot, accurate to ±.03 feet. The low steel or low concrete will be recorded on all bridges within the bounds of the stream profile. In rural areas, valley section profiles must be shot downstream for streams with drainage areas of more than 10 square miles. In urban areas, valley section profiles must be shot downstream for streams with drainage areas of 2 square miles or greater. All valley section profiles shall be shot at right angles to the streambed and shall cover elevations at least three feet above known high water marks, both right and left of the streambed. Valley section profiles shall also be shot at the narrowest point in the valley, which is within 1500 feet of the survey baseline or survey centerline. For additional information and an example, see attachment 4 & 4A. Information relating to the extreme high water history of a water shed at a bridge location will be documented in a field book or on the back of form 621004. For a field book example, see attachment 4b. 9

Drainage Plats Drainage plats shall be created using 1"= 660' scale aerial photos or geographically referenced digital images that can be referenced into Microstation files. The consultant must follow the guidelines below for creating a drainage plat: Water soluble ink shall be used on the 1"= 660' aerial photograph All survey baseline and stationing every 500 feet All ridge lines shall be inked on the photograph to show the sizes of drainage areas All drainage directions (flow arrows) shall be inked on the photograph The drainage area and character of watershed for any draw or stream within the bounds of the survey shall be inked on the photograph Ridge lines shall be field verified Drainage patterns and information shall be included in the topography notes On all draws, and side ditches,(that cross a survey baseline), the drainage area and character of the watershed must be noted on the photo * For an example (in English units), see attachment 5. USGS 7-minute quad maps or the publication "Drainage Area of Iowa Streams" may be used to calculate drainage areas for streams with drainage areas of 640 acres or more. However, the 1"=660' aerial photographs must be used for drainage area calculations less than 640 acres and may be used for any drainage area. Upon request, the Department of Transportation will furnish the 1"= 660' aerial photographs. However, all 1"= 660' aerial photos will remain the property of the Iowa D.O.T., and upon completion of the D1 event date, these photos must be returned to the Department. At stream or draw crossings, the consultant must obtain field located break lines Rt. and Lt. of survey baseline to a distance of 200 feet. These break lines will be on the stream banks, toe of banks, and the centerline of the stream. These elevations must be recorded to the nearest one-hundredth of a foot, accurate to ±.03 feet. Bridges Any mainline or side road bridge which has a span of 20 feet or more and which is within the survey boundaries must have a bridge sheet (Iowa Department of Transportation form 621004). These existing features will include: 1) Topography from 300 feet back of the existing bridge floor's beginning to 300 feet ahead of the existing bridge floor's end. This topography shall be right and left from the survey baseline to a distance of 200 feet. 2) Elevations along the field located break lines and elevations at field located spot locations within the boundaries of # 1 above. 3) Low steel or low concrete elevations at the abutments and piers on centerline. The consultant must provide ground profile and break points under the centerline of the existing bridge. 4) Contours labeled with elevation, and position & elevation of the stream centerline break line points, the edges of water points, and the banks for any stream or draw within the limits of #1 above. 5) Positions and elevations at the ends of all pier tops. These elevations and positions are to be at the centerline of the piers. 6) Positions and elevations at both ends of the existing bridge deck and at the centerline and gutter line of the bridge. 7) Positions and elevations at the ends of bridge rails and wings. 8) All other drainage structures with positions and elevations within the limits described in #1 above. 10

Culverts Any culvert, draw, side-ditch, or pipe which has a drainage area within the survey boundary must have a culvert sheet (Iowa Department of Transportation Form #621001). These existing features will include: 1) Topography 100 feet back and 100 feet ahead of where the culvert crosses the survey baseline, right and left to a distance of 200 feet. 2) Elevations along the field located break lines and elevations at field located spot locations within the boundaries of # 1 above. Elevations noted and labeled on a sketch of the following items: Top of Parapet ( Top of Head wall ) Tops of openings Top of trough Flow lines Dirt, apron, and scour flowlines Locations/elevations of flowlines at any breaks in the barrel 4) Contours covering the area mentioned in # 1 above J. General Because there are unique characteristics to each drainage way, a strict set of requirements for the ground survey is not always practical. In addition to the specifications listed in this document, the drainage survey could include additional information sufficient to complete hydraulic studies, to set culvert flow lines, and to position culverts or bridges correctly. K. Data Collection 1) Electronically collected unedited data files shall be submitted to the Iowa Department of Transportation in a format supported by the Department s mapping software. (Currently Geopak Survey) Field feature coding must be used in accordance with the Geopak.smd library available from the Office of Survey. (Geopak Survey supports most modern data collection formats) 2) A calculated coordinate ASCII file corresponding to the collected data shall be submitted. The format shall be comma separated as follows: Point Number,N,N,E,Z,Feature code (space) description of feature attributes 3) The Department will provide a project number to be used in the naming of all electronic field survey files. 11

L. File Naming PRELIMINARY SURVEY FILE NAMING CONVENTION FILE NAMING CONVENTION: T J J J J N N N WHERE: T=FILE TYPE J=PROJECT # FOUR CHARACTOR NUMBER ASSIGNED IN THE PROJECT (SAP #) N=FILE NUMBER (000,002,003,ETC-MAIN LINE) OR A01,B01,C01,ETC-SIDE ROADS) FILE TYPES J J J J 0 0 0 * J J J J 0 0 1, 002 & UP- * J J J J A 0 1, A02 & UP- * J J J J B 0 1, B02 & UP- * B J J J J N N N C J J J J N N N PJ J J J N N N EJ J J J N N N HJ J J J N N N CONTROL SURVEY - (Always the 000 file) SURVEY FILES( FIELD TOPO, DTM or X-SECTIONS) Mainline Files SURVEY FILES( FIELD TOPO, DTM or X-SECTIONS) Side Road A SURVEY FILES(FIELD TOPO, DTM or X-SECTIONS) Side Road B * NOTE: FILE NAME 7 CHARACTERS IN LENGTH NOT 8 BENCHES CONTROL FILE PHOTO CONTROL ELEVATION CONTROL HORIZONTAL CONTROL (ALIGNMENT OF BASELINES AND SIDE ROAD CL'S) I J J J J N N N VJ J J J N N N JJJJ.SUR INDEX FILE VALLEY SECTION MICROSTATION FILE WITH REQUIRED MODELS POINT NUMBERS- A point number should be used one time and one time only per project! 1-500 CONTROL POINTS & GPS POINTS 501-999 BENCHS 1000-1999 PHOTO CONTROL 2000-2999 PHOTO CONTROL 3000-3999 (IN HOUSE) PHOTO CONTROL PASS POINTS 4000-99,999 SURVEY POINTS FILE EXTENSIONS Filename.RAW Original Raw Field file. (Field observations) Filename.ASC Calculated coordinates of the UNEDITED.RAW field file. (Point Number,N,E,Z,Feature code (space) description of feature attributes) Filename.COR EDITED version of the.asc field file. (Point Number,N,E,Z,Feature code (space) description of feature attributes). Edited data includes corrections in feature coding and modifications to descriptions, etc. 12

M. PRELIMINARY SURVEY FILE TYPES Traverse Surveys A Traverse is defined as a series of courses and distances that forms a connection between two project control stations for supplemental horizontal control within the project. The traverse between the control monuments shall not exceed 2 miles in length. Two or more single traverses may be combined into one file. Each traverse must have an unadjusted error radius of not more than 0.15 on its closing point. Unedited traverse files will be furnished to the Department. Traverse error will be adjusted according to accepted survey standards. Critical control points on existing alignments included in the project will be included in the traverse or observed and adjusted by multiple Global Positioning observations. 000 Files Control Survey file These files include traverse files described above. This file naming convention is used by IDOT personnel to collect additional control along the survey corridor. In addition to the added horizontal control, all benches shall be tied to the traverse line between the known control stations. This file contains all raw field data to control points, benches, curve points and as-built control points within the survey corridor. Field Survey Files These files contain the majority of field data collected. Record all Topography and Data Terrain Model information in these files. The occupied station and backsight coordinates should be obtained from the control file. B-Bench Files The B files contain electronic 3-wire bench levels data. All bench levels shall be run by the three-wire method and checked by the loop system. A loop will be considered closed when a Datum bench (3rd order or better) is fixed at both ends of the run. Benches shall be recorded to the nearest one-hundredth of a foot and adjusted to the nearest one-thousandth of a foot in the adjustment report. An accurate description of the benchmark shall be recorded. The calculated version of this file shall have a.cal extension. Note: Benchmarks shall have the N, E, Z, value recorded in the (C- Control File) of the project. A stationoffset report of all project benches shall be created. General information and datum equation information shall be described in a narrative supplied the index file. If the bench data is not recorded electronically this data shall be recorded in a field book. A bench adjustment sheet shall be provided on all surveys. Digital levels may be used. Trig leveling and GPS derived orthometric heights (elevation) on benchmarks may be used provided the vertical accuracy in this specification [.05 X the square root of the circuit s length (in Miles)] can be verified. Such verification must be documented. 13

P-Photo Control When applicable, the consultant shall provide the essential ground control survey in electronic files using the preliminary survey file naming convention. Using this survey, the consultant shall then determine the horizontal positions and elevations of all horizontal and vertical control points required for the Photogrammetric compilation of planimetric and DTM data. The necessary horizontal control points shall be established in conjunction with an arbitrary local grid network chosen by the Iowa Department of Transportation. The standards for second-order horizontal control survey (Manual of Photogrammetry, 4th ed.) shall be attained (see page 422, 8.4.1.3, 1:10,000).. Horizontal Alignments Existing plan Horizontal alignments will be submitted in a Geopak database (.gpk) or in a format supported by Geopak software. V-Valley Section When a Valley Section is shot on a stream or river, record all information in a this file. I-Index File The Index file shall be supplied in electronic format and shall include a listing all of the submittal Items listed below. The report shall address the entire project and shall include all of the information necessary to find specific field data, datum information, etc. The report will include, but not necessarily be limited to, the following: 1. Introduction. The introduction shall include, but not necessarily be limited to, the following: The county. The project number. The project description. Time frame of the project ( i.e. arrival and departure dates of the field survey). Vertical Datum information of the project. Horizontal Datum information of the project. The name, mailing addresses, and phone numbers to the point of contact for which the survey was performed and the organization that performed the services. 14

2. Personnel. Personnel involved in the data acquisition; data processing, editing, GPS control and creation of the index. 3. Utility legend. A utility legend that clearly defines the feature codes, point descriptions and ownership of all utilities within the bounds of the survey. 4. Feature table used on the project, Control numbers used on the project, Bench numbers used on project, survey point numbers used on the project, and figure numbers used on the project. 5. File listing. A complete listing of all files submitted with the survey. Included with the file name narrative describing the type and location of the information associated with the file. 6. Notes submitted. A complete list of submittals. Iowa Department of Transportation Feature Codes and Mapping A feature code library is maintained by the Office of Survey. It is a Geopak Survey based (SMD) file that controls mapping of survey information into required models in a Microstation file with a.sur extension. The Office of Survey will provide the Microstation seed file and the smd.. A Geopak data file named (DDB) will be provided that contains custom tools used by the Iowa Department of Transportation to automate drawings. Instructions on using a Geopak library and tools will be provided to the surveyor or surveying firm. (SMD) and (DDB) files are subject to updating. Contact the Office of Survey for the most recent release. Consultant Project Submittal List before D1 event can be cleared Electronic files of the field survey Field Survey Information. All field survey data collector files shall be submitted electronically. Files shall include but may not be limited to the following: Traverse, Collection, Index, Control File, Bench Levels, Photo Control, and Alignment. Electronic file names shall conform to the IDOT naming conventions (See File naming section). All field books and/or files containing datum information, alignment information and equations to as built plans. Bench level adjustment information including identification number, station and distance out, horizontal coordinates, and final elevation for each benchmark. Alignment geometry in.gpk compatible format Control point references in a electronic Micro station "G sheet" format. (See Attachment) Culvert pink front/sheet (Form Nos. 621001) for each mainline and sideroad culvert. Bridge front/sheet (Forms Nos. 621004) for each bridge. Drainage Area information. Property owner information. 15

Utility Legend identifying ownership (with address and phone numbers) and reference to Micro station file. File containing Photo Control point information. File containing all index information outlined in this specification G sheet example 16