Chapter 4: Design Surveying

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Section 1: Descriptions and Definitions of Survey Types

Overview

Information contained in this section is the result of discussions of the Standing Committee on Surveying (SCOS), or is excerpted in its entirety and/or adapted for this manual from the Texas Society of Professional Surveyors, Category 6.

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Topographic Survey

A topographic survey is a survey performed to determine the configuration, relief or elevations of a portion of the earth’s surface, including the location of natural and/or man made features thereon. A topographic survey is necessary in order to prepare an accurate topographic map and requires the expert skill of a Registered Professional Land Surveyor (RPLS) well versed in maintaining accuracy and precision in detail mapping. Unless noted to the contrary, a topographic survey is not intended as a boundary survey, although some boundaries may necessarily be defined.

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Topographic Map

A topographic map is a two-dimensional (2-D) map that presents the horizontal and vertical positions of the features represented; distinguished from a planimetric map by the addition of relief in measurable form. A topographic map usually shows the same features as a planimetric map but uses contours or comparable symbols to show mountains, valleys, and plains.

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Planimetric Map

A planimetric map is a map that presents the horizontal positions only for the features represented; distinguished from a topographic map by the omission of relief in a measurable form.

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Digital Terrain Model (DTM)

A digital terrain model (DTM) is a mathematical model of a project surface that becomes a three- dimensional representation (3D) of existing and proposed ground surface features. Critical calculations and processes based on the DTM include contouring, cross sections and quantities, drainage models, watersheds, hydraulics, water catchment areas, and cross sections sheets.

A DTM is created through the construction of a Triangulated Irregular Network (TIN) and is based on modeling the terrain surface as a network of triangular facets that are created by simply connecting each data point to its nearest neighboring points. Each data point (having x, y and z coordinates) is the vertices of 2 or more triangles. The advantage of the TIN method is its mathematical simplicity- all DTM calculations are either linear or planar.

The processes and the resulting DTM offer many advantages over a topographic survey. Field data for a DTM is collected in a way that allows TxDOT to use the latest in automated survey technology. Traditional data collection (for a topographic survey) involves taking cross sections, typically every 100 feet, along a horizontal control line or in a grid pattern. Digital terrain modeling has virtually eliminated this practice.

Data points (shots) are taken at every break in elevation with no particular pattern being required. The emphasis is on identifying all features and changes in elevation within project limits. Data is collected using an electronic data collector with an electronic total station. The data points are assigned feature codes, attributes, descriptions, comments, and connectivity linking codes to add intelligence to a point at the time of data entry into data collector.

Information is downloaded from the data collector to a computer, either in the field or later in an office, and is processed using AASHTOWare^® Survey Data Management System^®(SDMS) software. A SDMS^® calculated file is generated for importation into CAiCE^™ or GEOPAK Survey^™ for further review. The file is then imported into GEOPAK^® for project design.

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Route Survey

A route survey is an application of the above described topographic or DTM survey along a determined linear ROW route, either existing or proposed, for a utility or roadway.

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Purposes

A topographic survey is made for the purpose of gathering relevant information that will be represented on either a topographic map or in a DTM. Typically, highway planning, engineering design and ROW design are the primary purposes.

Special Note For TxDOT Purposes. When this text discusses procedures or standards relating to either a topographic survey or survey for a digital terrain model, the accuracy, standards, equipment and basic procedural methods employed will be the same. A topographic survey will be performed and a DTM can be used for most all TxDOT applications where route design and engineering are required, whereas a topographic map may be better suited for large area site design and development.

This specification is intended for use in developing a design survey, a digital terrain model, or a topographic survey, with accuracy sufficient to meet TxDOT design needs and requirements.

A 3D model or a DTM may be preferred for purposes such as:

highway/roadway planning, design
ROW design
drainage studies
site development, planning
architectural planning, design
landscape design.

A significant advantage of a DTM is that it offers the ability to view, inspect, and smoothly navigate through, over and across a DTM in a 3D environment for the purposes of locating, editing, and correcting raw field data (points and chains) in 3D.

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Considerations - Other Technology

A computer model or a DTM is the ultimate work product of any of these newer methods of data acquisition. Depending on the critical factors of each project, including type, terrain, accuracy, precision required, cost, traffic conditions, and safety, such advanced methods may warrant serious consideration as a compliment to conventional data gathering or as a replacement of common or conventional surveying methods.

While conventional aerial photogrammetry may still be viable; however, as technology continues to advance, existing methods such as photogrammetry with airborne Global Positioning System (GPS) control become more accurate and even more cost effective. Other newer methods of terrain modeling are also available. One such method is airborne Light Detection and Ranging (LiDAR), which is a laser imaging scan done from a helicopter. Another, more advanced method is FLIMAP, or Fast Laser Imaging Mapping and Profiling, which employs laser scanning, incorporated with GPS for navigation and position. A DTM is produced as the deliverable.

Ground based LiDAR is an automated collection of data by reflector-less laser which involves high density scanning of an object or location to collect a “point cloud” of data points. The point cloud of data is further processed into a 3 dimensional computer model image. Typically done from a remote instrument location or multiple locations, 3D Laser scanning is especially good for sites or objects that are difficult to access, have high traffic volumes, involve extreme detail or have other extreme dangers or conditions associated.

This method has also been utilized in place of conventional topographic or digital terrain model (DTM) surveying with much success, especially where high traffic volumes or lane closure issues (safety) were critical factors. Presently the accuracy of the scanned data is said to equal or even exceed that of conventional survey methods, even electronic total station work, with the additional advantage of a greater number of data points all throughout the structure or project. Other methods or technology should be discussed with and approved by the district survey coordinator before use.

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Work Product

A DTM or Topographic Survey requires:

A control survey network, with horizontal and vertical positions on primary control points that are monumented, referenced, and placed near or on the project site.
Points of secondary control, which are based upon and supplement primary control to facilitate data acquisition within a project.
A description and location sketch of each control point.

See Chapter 3, Preliminary Surveying, for specifications on horizontal and vertical control networks and information on point descriptions, location sketches, and other pertinent information.

While a topographic map (2 dimensional) may be the typical end product of a topographic survey, for TxDOT purposes a processed computer file for a DTM (3 dimensional) is the primary deliverable product. Even when hard copy maps are specified as a part of the deliverable, electronic graphics files (2D and/or 3D) for the final product must be furnished to TxDOT for each project.

Required files include:

Computer files of collected raw data, as required by the respective TxDOT office. These computer files should at a minimum, consist of raw, unprocessed data as originally collected in the field by Survey Data Management System^® (SDMS) or other approved, TxDOT supported data collection method and software.
Processed data in a form that is fully compatible and usable in TxDOT supported software programs such as CAiCE^™, GEOPAK^®, and MicroStation^®.

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Information Required

The Standing Committee on Surveying (SCOS) has adapted and approved information within this subsection from the Texas Society of Professional Surveyors, Category 6.

Information may be furnished to the surveyor by TxDOT, or the surveyor may be required to research TxDOT files and/or public records, if so directed and agreed upon. Information should include the following:

project or site location shown on a map
ROW maps depicting current ROW width(s) and other land, ownership and survey information
ownership information of adjacent tracts
intersecting road ROW information, documentation
construction plans of existing facilities if available
intended use of the survey and required form of deliverable, files required, etc.
accuracy required and method of display (contours, spot elevations, etc.)
horizontal and vertical datum upon which the survey should be based if this varies from the TxDOT standard. Example: match existing project datum instead of NAD 83 or NAVD 88
availability and need of special data, whether current or historic, which may include: Existing data or mapping from other agencies, county, flood control/drainage district, FEMA, Corps of Engineers, etc.
for state forces and all consultants, permission must be secured prior to entry on private property to survey outside of state ROW
research on subject tracts/parcel ownership also includes name(s) of tenants or parties in charge and special conditions or considerations required or requested by the owner
existing National Geodetic Survey (NGS) and/or United States Geological Survey (USGS) survey control information and data sheets for horizontal and vertical monumentation
recent aerial photographs (particularly for large sites), USGS quadrangle sheets, or computer files of the same.

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Monuments

Reference points and control monuments for a topographic survey may include temporary stakes, hubs, nails in pavement, iron rods, or reinforced concrete monuments.

A wooden hub or stake, nail or iron rod is considered as secondary control (temporary bench mark or control point) which only supplements primary survey control monumentation to facilitate data acquisition.

Primary control points, whether set by GPS or conventional survey methods, shall be of reasonable permanence and should conform to the requirements and specifications shown in Appendix C, “Monumentation” of this manual.

A “datum point” rod or a rock setting is required for GPS Level 1 control points, but the “standard” TxDOT concrete setting can be used for GPS Level 2 surveys. The standard concrete setting was formerly depicted in the old M-92 drawing for Right of Way (ROW) monuments.

Control monuments shall be well referenced, named according to district procedure, indexed in the project data or field notes and identified in the computer file final deliverable. Point names may be furnished for a state-wide or a district monument numbering system by the TxDOT District Survey Coordinator. A location sketch and data sheet for each monument should be furnished to the project manager prior to completion of work.

Example of a monument stamping: 000-0000

where, 000 refers to the County number
and 0000 refers to a discrete monument number for each district and is determined by district surveyor personnel.

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Monumentation for New Stations

All monumentation for new Level 1 points are to be in accordance with the following NGS publications:

Concrete Marks, from NGS Operations Handbook and Manual of Geodetic Triangulation, S.P. 247.

Setting a Survey Disk in Bedrock or a Structure from NOAA Manual NOS, NGS 1, Geodetic Bench MarksSetting a NGS 3-D Monument Based on Revised NGS 3-Dimensional (3-D) Rod Mark [Draft Version] by: Curtis L. Smith, National Geodetic Survey, July, 1996.It is recommended that new Level 2 points also follow these construction specifications, but the TxDOT surveyor in charge may call for less stringent requirements.

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Naming Convention for Level 1 and Level 2 Monuments

The recommended naming convention for Level 1 and Level 2 monuments is as follows:

Example: 1580032

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Digits	Indication
158	The first three (3) digits indicate the county in which the monument was set. This is the standard county code used by TxDOT.
0032	The next four digits indicate the point number of this particular monument. It is specific for this county and there can be no duplicates in the county.

Some districts use variations of this by including a prefix or suffix.

Figures 4-1 and 4-2 are sample data sheets for documenting the monuments likely to be used in the future. There must be a data sheet for all Level 1 and Level 2 monuments. Districts may use their own data sheet form; however, it must contain all the horizontal and vertical geodetic data of these sample data sheets. An RPLS signature and seal is recommended for data sheets for Level 1 and Level 2 GPS monuments.

The following table provides a list of the standard county designator codes used by TxDOT.

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County #	County Name	County #	County Name	County #	County Name	County #	County Name
1	Anderson	65	Donley	130	Kaufman	193	Real
2	Andrews	67	Duval	131	Kendall	194	Red River
3	Angelina	68	Eastland	66	Kenedy	195	Reeves
4	Aransas	69	Ector	132	Kent	196	Refugio
5	Archer	70	Edwards	133	Kerr	197	Roberts
6	Armstrong	72	El Paso	134	Kimble	198	Robertson
7	Atascosa	71	Ellis	135	King	199	Rockwall
8	Austin	73	Erath	136	Kinney	200	Runnels
9	Bailey	74	Falls	137	Kleberg	201	Rusk
10	Bandera	75	Fannin	138	Knox	202	Sabine
11	Bastrop	76	Fayette	142	La Salle	203	San Augustine
12	Baylor	77	Fisher	139	Lamar	204	San Jacinto
13	Bee	78	Floyd	140	Lamb	205	San Patricio
14	Bell	79	Foard	141	Lampasas	206	San Saba
15	Bexar	80	Fort Bend	143	Lavaca	207	Schleicher
16	Blanco	81	Franklin	144	Lee	208	Scurry
17	Borden	82	Freestone	145	Leon	209	Shackelford
18	Bosque	83	Frio	146	Liberty	210	Shelby
19	Bowie	84	Gaines	147	Limestone	211	Sherman
20	Brazoria	85	Galveston	148	Lipscomb	212	Smith
21	Brazos	86	Garza	149	Live Oak	213	Somervell
22	Brewster	87	Gillespie	150	Llano	214	Starr
23	Briscoe	88	Glasscock	151	Loving	215	Stephens
24	Brooks	89	Goliad	152	Lubbock	216	Sterling
25	Brown	90	Gonzales	153	Lynn	217	Stonewall
26	Burleson	91	Gray	154	Madison	218	Sutton
27	Burnet	92	Grayson	155	Marion	219	Swisher
28	Caldwell	93	Gregg	156	Martin	220	Tarrant
29	Calhoun	94	Grimes	157	Mason	221	Taylor
30	Callahan	95	Guadalupe	158	Matagorda	222	Terrell
31	Cameron	96	Hale	159	Maverick	223	Terry
32	Camp	97	Hall	160	McCulloch	224	Throckmorton
33	Carson	98	Hamilton	161	McLennan	225	Titus
34	Cass	99	Hansford	162	McMullen	226	Tom Green
35	Castro	100	Hardeman	163	Medina	227	Travis
36	Chambers	101	Hardin	164	Menard	228	Trinity
37	Cherokee	102	Harris	165	Midland	229	Tyler
38	Childress	103	Harrison	166	Milam	230	Upshur
39	Clay	104	Hartley	167	Mills	231	Upton
40	Cochran	105	Haskell	168	Mitchell	232	Uvalde
41	Coke	106	Hays	169	Montague	233	Val Verde
42	Coleman	107	Hemphill	170	Montgomery	234	Van Zandt
43	Collin	108	Henderson	171	Moore	235	Victoria
44	Collingsworth	109	Hidalgo	172	Morris	236	Walker
45	Colorado	110	Hill	173	Motley	237	Waller
46	Comal	111	Hockley	174	Nacogdoches	238	Ward
47	Comanche	112	Hood	175	Navarro	239	Washington
48	Concho	113	Hopkins	176	Newton	240	Webb
49	Cooke	114	Houston	177	Nolan	241	Wharton
50	Coryell	115	Howard	178	Nueces	242	Wheeler
51	Cottle	116	Hudspeth	179	Ochiltree	243	Wichita
52	Crane	117	Hunt	180	Oldham	244	Wilbarger
53	Crockett	118	Hutchinson	181	Orange	245	Willacy
54	Crosby	119	Irion	182	Palo Pinto	246	Williamson
55	Culberson	120	Jack	183	Panola	247	Wilson
56	Dallam	121	Jackson	184	Parker	248	Winkler
57	Dallas	122	Jasper	185	Parmer	249	Wise
58	Dawson	123	Jeff Davis	186	Pecos	250	Wood
62	De Witt	124	Jefferson	187	Polk	251	Yoakum
59	Deaf Smith	125	Jim Hogg	188	Potter	252	Young
60	Delta	126	Jim Wells	189	Presidio	253	Zapata
61	Denton	127	Johnson	190	Rains	254	Zavala
63	Dickens	128	Jones	191	Randall
64	Dimmit	129	Karnes	192	Reagan

Figure 4-1. TxDOT Control Point Data Sheet.

Figure 4-2. Sample Project Specifications Control Point.

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Conditions

The effect of location, such as rural, suburban, urban, or urban business district, on conditions of a DTM or topographic survey will be minor and will be most dependent upon the purpose of the survey.

The need for appropriate control and tolerances will be the deciding factor when the purpose of the survey is for roadway or ROW design in determining reasonably accurate quantities of construction materials, such as water, spoil, fill, concrete, etc.

For TxDOT needs, the following shall be covered under Condition I regardless of location (rural or urban), unless TxDOT gives directed and prior approval:

roadway design
bridge design
ROW design
environmental site
historical site.

Extended area topography (i.e.: drainage area outside of a ROW) may fall under Condition II, but is subject to direction by the TxDOT project manager.

DTM and topographic survey tolerances are typically confined to the Condition I and II.

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Field Procedures

DTM or topographic surveys require a reliable horizontal and vertical control system based on acceptably closed and adjusted traverses and level loops. Attention should be given toward developing this control system before any detail work is begun.

Field work shall be performed to achieve the specified or intended accuracy and results as stated in this manual, in accordance with accepted technical methods, i.e.: TxDOT, NGS, or the TSPS Manual of Practice, and as directed by the manufacturer of the surveying instrument(s) or equipment used.

For GPS applications, the Federal Geodetic Control Subcommittee’s (FGCS) Geometric Geodetic Accuracy Standards and Specifications for Using GPS Relative Positioning Techniques shall be followed.

Field personnel shall be well trained in the technical aspects of surveying as related to their respective duties.

Surveying instruments shall be checked and kept in close adjustment according to their manufacturer’s specifications or in compliance with textbook standards.

Electronic distance measuring devices shall be compared against a standardized baseline at 6 month intervals, however a comparison check should always be done as needed, especially if an instrument has been dropped, damaged or is suspect of the same. A calibrated baseline certified by NGS is the preferred standard.
This comparison includes electronic total stations or any other electronic measuring instrument, and may be done by more up to date methods as agreed upon by TxDOT.
Total stations and theodolites shall be compared against a standard known angle at a 6 month interval; however, a comparison check should always be done as needed, especially if an instrument has been dropped, damaged or is suspect of the same.
Levels, auto or digital should be checked by the “2 peg test” or the reading the elevation difference between two reference points taken from 1.) a middle setup between points and also 2.) from an end setup. Failure to get the same difference of elevation indicates an out of adjustment condition, which usually requires a shop cleaning and adjustment.
Auxiliary tapes, cloth or fiberglass, shall only be used for rough measurements where precision is not important, such as determining the width of ditches, the location of excavations or other irregular improvements. Tapes of this sort shall not be used to measure distances in excess of 100 feet.

Field measurements of angles and distances shall be performed in such a manner as to attain the closures and tolerances as found in this manual and see Table 4.4 TSPS Manual of Practice Chart for Tolerances for Conditions, at the end of this section.

Surveys for vertical or horizontal monumentation for control of a DTM or a topographic survey shall refer to the following sources:

TxDOT Survey Manual
NGS special publications
NGS standards for horizontal or vertical control monuments that will be registered
Department of the Army ( Corps of Engineers).

Where aerial photogrammetry is to be used to compile the topographic map, the surveyor shall consult with the photogrammetrist as to specific requirements for the photo control and for additional supplemental information required by conditions of a specific project or location.

Horizontal and vertical photo control (picture points) shall be based on and looped to the control system.
Identification of photo control (picture points) must be precise and clear since these points will be used to build the network from which the photogrammetrist must work.
Photo control points, set before the aerial photography is made, shall be located from, and looped to the control system. The density and pattern for paneled picture points shall be determined through consultation and coordination with the photogrammetrist.

For TxDOT purposes, methods that are more modern are normally used such as the DTM survey that incorporates methods described in the section below.

Surveying procedures with electronic total station or with GPS shall incorporate control points that are tied to a primary control system network of an appropriate level of precision and accuracy for the project.

Acquisition of field data may require running secondary control and bench marks that begin and end at points on the primary control system.

The use of open ended legs or “spur” lines should be avoided whenever possible. When such lines are necessary, appropriate checks shall be made on all field data before leaving the vicinity.

Any field notes written in a field book shall be kept in a neat and orderly manner on all control points, primary or secondary. Appropriate annotations on location, description of point and reference to identifying specific features located during the DTM or topographic survey shall be made.

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Topographic Features

The perimeter limits of any unique or special features such as historical structures, cemeteries, burial grounds or grave sites known or found within the project limits or adjacent to and which may be affected (existing or proposed ROW) and shall be shown by actual location.

Buildings and improvements, including distance from proposed ROW up to 50'. See Chapter 5, ROW Surveying of this manual and the TxDOT ROW Manual Volume 1 - Procedures Preliminary to Release. The project manager and/or district surveyor may extend this distance in the following ways:

center lines of dry creeks, gullies or other confined intermittent watercourses
paths, car trails, pasture roads, etc.
borders, boundaries - city limits, county line or state line
additional data points shall be collected along such features, outside of state ROW, as required and directed by TxDOT. These additional features may include:
- creeks, streams, rivers and water bodies, shown and identified by name. Water levels shall be determined and displayed by elevation, time, and date of observation.
- drainage areas - field information on drainage area(s) of a project shall be collected in the same manner as other information to the extent as directed by the project manager and/or district surveyor.

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Electronic Data

In nearly all cases, field work is automated by the use of computer software and hardware for collecting, reviewing, editing and processing field data. A data collector may be connected to the instrument (total station, GPS receiver, digital level, etc.) to store the raw measurement data and perform coordinated geometry (COGO) functions while in the field. Original raw data must be saved as a file for retention, as a matter of record, before any data editing or processing is done.

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Data Collection

Field data in electronic form should be collected in the SDMS^® collection form and processed in SDMS^® Processor. This software was developed through the American Association of State Highway and Transportation Officials (AASHTO) and supported by TxDOT Technology Services Division. It is provided gratis to TxDOT consultants under TxDOT’s license agreement with AASHTO. Its purpose is to provide a more flexible and user definable method of recording horizontal angle, vertical angle and slope distance from most of the total stations and in a standard format recognized by the survey review or design software.

There are numerous ways to provide connectivity. When performing radial topography surveys for a DTM, points in the same chain such as edge of pavement, centerlines and ditch lines can be linked together. These survey chains can ultimately be ported to mapping files or to DTM files as DTM break lines. Standard TxDOT feature codes and cells have been developed for use in the field to insure standardization of line weight, color, levels, and symbology.

These feature codes also determine where the points and chains will go, either to a mapping file or a DTM file. Topographic surveys, traverses and level runs may be collected in Survey Data Management System^® (SDMS) Collector software. The data can then be reduced to coordinates on a desktop PC using SDMS^® Processor, which uses a least squares type of adjustment. There are a number of useful reports that can be generated in this software.

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Office Analysis

Survey review and DTM - In order to view the results of a survey for troubleshooting and delivery of a .dgn file, pre-design software will be used. TxDOT uses CAiCE^™ Visual^® Transportation, GEOPAK Survey^™, and SDMS^® Processor to serve as the tool(s). This software will accept the SDMS .cal file as input with the TxDOT feature table attached, and will graphically display the project for analysis. Corrections and additions can be made and the DTM can then be created. Photogrammetry files, background maps, macros for visualization and other enhancements may be utilized before 2D or 3D graphics are exported as a .dgn file for GEOPAK^® / MicroStation^® use by the designer.

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TxDOT Deliverables - Computer Files, Maps, and Drawings

Printed maps or plan sets of topographic surveys or digital terrain model (DTM) shall be represented by neat, reproducible drawing sheets. These drawing sheets are plotted for urban projects at a typical scale of 1'' = 50' (Full Size or scale) or 1'' = 100'. Half size, scale, or rural projects may use a typical scale of 1'' = 100' and 1'' = 200', unless otherwise approved or directed and shall accurately depict the results and details of the field work, research, and computations as compiled and checked.

For initial submission, plotted drawings may be on paper, in the same sizes listed above, in a size prescribed by TxDOT graphics standards, the TxDOT ROW Manual Volume 1 - Procedures Preliminary to Release, or as requested by the TxDOT project manager. Information may also be submitted in electronic form according to district standards.

For the TxDOT final work product, all final drawings shall be plotted on Mylar film medium and other typed documents on a quality bond paper. All drawings and the information shown shall be plotted or printed on standard sizes and shall be according to TxDOT graphics standards, the TxDOT ROW Manual Volume 1 - Procedures Preliminary to Release, or standards contained in this manual, as may be applicable.

Typically, full size drawings shall be plotted on 22'' x 34'' medium. Half (½) scale drawings shall be on an 11'' x 17''size medium. Bond paper may be used for initial submittal. Mylar shall be used for all final drawings.

No plat, map or drawing shall be made on a sheet size smaller than 8 ½'' x 11''

All information, existing topographic features, monuments - ROW or control monuments, or property corners, whether found or set, etc. shall be represented on a map and in the computer file(s), in the proper dimensioned location by using the most current TxDOT cell library (example: TxDOT2K.cel) for symbol standardization. Some projects (i.e.: ROW acquisition) may require that other features are labeled and dimensioned as to size, height, width, or depth and referenced to the nearest ROW or property line. Site maps for architectural design may require other symbology.

All maps or drawings, whether printed, plotted or in a computer file shall have a north arrow and shall be oriented so that north is toward the top of the sheet unless otherwise directed by TxDOT.

The Texas Coordinate System, based upon NAD 83 (HARN), shall be used with the proper zone, adjustment factor, theta angle and reference monument information used shall be noted.

For TxDOT purposes, a statement containing the above information shall be placed on all drawings and/or included with all computer files that provide reference information or “metadata” on the control monumentation, NGS, or other that is used as a basis for all projects.

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Title Sheet

A title/cover sheet shall be prepared for each project (examples accessed from TxDOT ROW Manual Volume 1 - Procedures Preliminary to Release, and shall show the following items:

location of the route or project being mapped shall be shown on a title/cover sheet prepared for each project
appropriate location sketch
station numbers of the projects beginning and end
charge numbers (CSJ, both Construction and ROW)
stated scale of the drawing with a graphic scale
project description
survey date
larger projects, a sheet index may be preferred
statement of the basis for horizontal and vertical control, including information listed in sections below
if prepared by a consultant, the company name, address and phone number shall be shown.

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Horizontal Control

Horizontal control deliverables shall include the following:

For TxDOT purposes, the Texas Coordinate System of 1983/93 HARN adjustment shall be used.
Map coordinates and distances shall be in surface measurements and the combined adjustment factor (CAF) must be indicated to allow for return to state plane coordinates (SPC).
A statement shall also be made specifying the proper zone, referenced traverse or triangulation station(s), and the published coordinates of the station(s) used along with elevation.
The appropriate mapping angle (theta angle) for the site shall be shown on the map.

It should be noted that the TxDOT Surface Adjustment Factor (SAF) is the reciprocal of the CAF.

As mentioned, TxDOT works in surface coordinates, but project size/length, number of counties or SPC zones crossed or other factors may justify showing all information in grid coordinates.

Unless otherwise directed by TxDOT, all deliverables shall be fully compatible with CAiCE^™ and/or GEOPAK^® and be native MicroStation^® files. Graphics standards are available from TxDOT.

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Vertical Control

Typically, TxDOT elevation basis is either 1.) an existing project (datum specified by project) or 2.) NAVD 88.

A statement of the basis of elevations shall be made in computer files and placed on all map prints similar to one of the following examples:

Elevations refer to a BM set near the N. E. corner of the intersection of First St. and Ave. B (Location), an “X” on top of a concrete inlet (description). Elevation is 200.00 ft., and is referenced datum of Project CSJ 0000-00-000.
Elevations are based upon NGS bench mark A1422, NAVD 88, Published elevation—326.042 ft. (1988 Adjustment).

Per TxDOT policy (see Contract for Surveying Services) and as agreed to in survey contracts with the state, all original work products become property of the state. A consultant performing work under contract with the state may keep a copy for company records.

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Control Point Data Sheets

A data sheet shall be provided for individual Level 1 and Level 2 control points. It should contain, at a minimum, the information noted below:

Anchor: #i1000055Table 4.3 Control Point Data Sheets
Established by	contractor company
Date established	date monumented
TxDOT Level of Survey	e.g. Level 2
Horizontal Datum	e.g. NAD83
Horizontal Adjustment	e.g. '93 HARN
State Plane Projection Zone	e.g. Tx South Central 4204
Vertical datum	e.g. NAVD88
Geoid model used	e.g. GEOID03 or GEOID99
Units	US Survey foot
County name	e.g. Bexar
Station name	e.g. 0150102
Latitude	Latitude to 5 decimal places
Longitude	Longitude to 5 decimal places
Northing	three decimal places
Easting	three decimal places
Elevation	two decimal places
Convergence angle	nearest second
Combined Adjustment Factor	eight decimal places
Survey method for vertical	GPS or leveling
General location	e.g. S Loop 1604 W & FM2790
To Reach description	how to get to station from a well known intersection
Type of Mark	iron rod, brass disc, etc.
Stamping	what is actually stamped on the disk
Stations directly tied	list up to three closest stations directly tied

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Certification

While TxDOT contract requirements call for supervision and monitoring by a Registered Professional Land Surveyor (RPLS) signing and sealing a topographic survey, a digital terrain model (DTM) or preliminary design survey is not usually required, but may be called for by district standards.

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Right of Way - Descriptions with Plats (Exhibit A) and ROW Maps

If descriptions and plats of parcels become necessary for ROW acquisition, all descriptions and plats (combined as property descriptions and labeled as TxDOT Exhibit A of the ROW Map package), shall be prepared according to Chapter 5, ROW Surveying of this manual and the TxDOT ROW, Volume 1 - Procedures Preliminary to Project Release. Any additional information needed or required by the district shall also be included as directed.

The following chart is excerpted from the TSPS Manual of Practice.

Anchor: #i1002535Table 4.4 TSPS Manual of Practice Chart for Tolerances for Conditions
Condition	I	II
	Urban Business, District Urban, Suburban & Industrial	Rural & Broad Area General Mapping	Remarks & Formulae
Error in Traverse Closure	1:10,000	1:7500	System Control Loop
Unadjusted Level Loop Closure (ft.)	.04	.08	System Control Loop M=Miles
Secondary Traverse Closure	1:7500	1:5000	Between System Control Points
Secondary Level Loop Closure (ft.)	.05	0.2	Between System Control Points
Positional Error of Any Primary Monument (horizontal)	1:15000	1:10000	For monuments used for Triangulation or Radial Surveying in respect to another
Positional Error of Any Primary Monument (vertical)	± .03 ft.	± 0.15 ft.	For permanent bench marks
*Contour Interval	2 ft.	10 ft.	Or as needed by the State
Contour Accuracy	± ½ Contour Interval	± ½ Contour Interval
Positional error of any Photo Control Point (horizontal and/or vertical)	0.50 ft.	2 ft.	Or as recommended by Photogrammetrist
Location of Improvements, Structures, and Facilities during survey	± 0.05 ft. ± 0.50 ft.	± 0.1 ft. ± 1 ft.	Vertical (inverts, flow lines) Horizontal
Plotted location of Improvements, etc.	± 1/40 in.	± 1/40 in.	Symbols may be used for large scale maps indicating Center point
Scale of maps sufficient to show detail, but no less than	1'' – 200'	1'' – 2000'	Drawings are to show location of survey monuments and bench marks