meeting the odot survey & mapping...

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Meeting the ODOT Survey & Mapping

SpecificationsA Simple Solution

Presented by Ray Foos, P.S, ODOT CADD & Mapping Services

& Jon Keller, P.S., ODOT District 3

Field Work

Phases of an ODOT Survey Project

Research

Processing Deliverables

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But First Things First…

Equipment Calibration

Property Owner Notification Letters

(Give the dog a head’s up.)

OUPS

Equipment Calibration and Maintenance

603 Equipment Calibration and Maintenance

Ensure all surveying equipment is calibrated and adjusted in accordance with the manufacturer’s recommendations. Documentation of all equipment adjustments and calibrations shall be kept and made available to ODOT upon request. Refer to the following criteria as a minimum for equipment maintenance:

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603.1 Levels

Ensure professional calibration and servicing is performed per the manufacturer’s specifications.

In addition, perform maintenance and care according to the following schedule:

Every 3 Months:

Clean and inspect optics, electrical contacts, instrument body, and instrument case

Check and adjust level vials

Peg test the level and adjust as needed

603.2 Total Stations Ensure professional calibration and servicing is performed per the

manufacturer’s specifications.

In addition, perform maintenance and care according to the following schedule:

Every 3 Months:

Clean and inspect optics, electrical contacts, instrument body, and instrument case

Check and adjust level vials

Check and adjust vertical plummet

Every 6 Months:

Check horizontal and vertical circle collimation and adjust as needed

Check calibration of E.D.M. on a baseline and adjust as needed

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603.3 Tripods, Tribrachs, Prism Rods, and RTK Rods

Perform maintenance and care according to the following schedule:

Every 3 Months:

Clean and inspect

Adjust level vials

Adjust the optical plummet

Tighten all clamps, locks, feet and screws to the proper specification

Calibration Baselines

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Method used to measure a Baseline

0 meters 120 meters 900 meters 1320 meters

Starting at the 0m mark take 10 measurements (5 direct/5 reverse) to the remaining three monuments.

Record your observations:



Move to the 120m mark take 10 measurements (5 direct/5 reverse) to the remaining three monuments.

Record your Observations:

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Here’s what we do with the DATA

Property Owner Letters

501.1PropertyOwnerNotificationofEntry

Survey crews performing work for the Department are granted access to private land per O.R.C.163.03 & O.R.C. 5517.01. Property owner notification is required at least 48 hours in advance. A standard property owner notification form is included in Appendix G. Both ODOT and consultant surveyors are responsible for any damage to the property of others incurred during the process of their work. Should any damages occur; the survey crew chief will document the damage and deliver a report to the District.

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Research

County Engineer, Auditor & Recorder Offices Most state highways were formerly county roads

Research

State Route numbers are not forever Current State Route numbering system was preceded by the Inter-County Highways

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Research

Plans Field Books ROW Monument Reports

Available from ODOT:

Contact District 3 Survey for Records

Scott Hawkins, P.S. (Survey) [email protected]

(419) 207-2823

Jon Keller, P.S. (Survey) [email protected]

(419) 207-7030

James Kenyon, P.S. (Real Estate) [email protected]

(419) 207-7112

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Research

Local boundary surveys

Sometimes that’s all you’ve got!

Field Work: Setting Control

This satisfies sections

502.1 – 502.2.D of the Surveying & Mapping Specifications for Minor Projects

502.1 – 502.2.D

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BUT FIRST!!!

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YOU DIDN’T THINK YOU WERE GOING TO GET THROUGH TODAY WITHOUT TALKING ABOUT STATE PLANE COORDINATES?

DID YOU?!?

GOOD COORDINATION BEGINS WITH GOOD COORDINATES

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State Plane Coordinates 101:

The Shape of the EarthEarth is not flat

Earth is not a sphere

An ellipsoid is a simplified model of Earth’s Shape

A datum is a set of reference locations, including elevations, describing more precisely the surface of the Earth

THE ELLIPSOIDMATHEMATICAL MODEL OF THE EARTH

a = Semi major axisb = Semi minor axisf = a-b = Flattening

a

b

a

N

S

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UNITED STATESELLIPSOID DEFINITIONS

CLARKE 1866a = 6,378,206.4 m 1/f = 294.97869821

GEODETIC REFERENCE SYSTEM 1980 - (GRS 80)a = 6,378,137 m 1/f = 298.257222101

WORLD GEODETIC SYSTEM 1984 - (WGS 84)a = 6,378,137 m 1/f = 298.257223563

BESSEL 1841a = 6,377,397.155 m 1/f = 299.1528128

State Plane Coordinates 101:

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COMPARISON OF DATUM ELEMENTS

NAD 27 NAD 83

ELLIPSOID: CLARKE 1866 GRS80a=6,378,206.4 m a=6,378,137 m1/f = 294.9786982 1/f = 298.257222101

DATUM POINT: Triangulation Station Earth Mass CenterMeades Ranch, Kansas

ADJUSTMENT: 25k Stations 250k Stationsfew hundred Base lines 30k EDMI base linesfew hundred Astro Az 5k Astro Azimuths

Doppler and VLBI

BEST FITTING: North America World-Wide

NAD 27 and NAD 83

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VERTICAL DATUMS

MEAN SEA LEVEL DATUM OF 1929

NATIONAL GEODETIC VERTICAL DATUM OF 1929

(As of July 2, 1973)

NORTH AMERICAN VERTICAL DATUM OF 1988(As of June 24, 1993)

NGVD 29 and NAVD 88

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GEOID

► The GEOID is the equipotential surface of the Earth’s gravity field which closely approximates mean sea level.

► The GEOID surface is perpendicular to gravity at all points.

► Vectors of the direction of gravity do not all point to the center of the earth’s mass.

► GEOID surface is irregular and undulates.

ELLIPSOID - GEOID RELATIONSHIP

H h

EllipsoidGRS80

H = Orthometric Height (NAVD 88)

N

Geoid

H = h - Nh = Ellipsoidal Height (NAD 83)N = Geoid Height (GEOID 12A)

GEOID12A

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THE GEOID AND TWO ELLIPSOIDSTHE GEOID AND TWO ELLIPSOIDS

GRS80-WGS84CLARKE 1866

GEOIDEarth MassCenter

Approximately236 meters

OHIO STATE PLANE ZONES - NAD83

► LATITUDE 41° 42’ N► NORTH ZONE► LATITUDE 40° 26’ N► ORIGIN LAT 39° 40

X=600,000 m, Y=0 m

► CENTRAL MERIDIAN► LONGITUDE 82° 30’ W

► LATITUDE 40° 02’ N► SOUTH ZONE► LATITUDE 38° 44’ N► ORIGIN LAT 38° 00’

X=600,000 m, Y=0 m

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Gratuitous Disclaimer Time!!!

Warning!!! The following content is the methodology and reasoning used by the Surveyors at ODOT District 3 for scaling grid coordinates to ground. It is not to be construed as standard practice for all of ODOT. You must contact each individual ODOT District Survey Operations Manager to determine the method used and final deliverable for their respective Districts.

Grid to Ground and State Plane Coordinates Why do we worry about this?

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Ohio Revised Code157.03 Plane co-ordinates; description

The plane co-ordinates of a point on the earth’s surface, to be used in expressing the position or location of such point in the appropriate zone of the systems specified in section 157.01 of the Revised Code, shall consist of two distances, expressed in United States survey feet and decimals of a United States survey foot when using the Ohio co-ordinate system of 1927, and expressed in meters and decimals of a meter when using the Ohio co-ordinate system of 1983…

We find the practice of having Grid coordinates in meters and Ground coordinates in feet a simple and effective way to distinguish between the two systems.

Ohio Revised Code157.04 Evidence of corner location, purchaser need not rely on system description

Plane co-ordinates, used to reference and describe land boundary corners and made part of the recorded description of such corners, shall be considered adequate evidence of the location of such corners in the absence of original physical monuments or other acceptable controlling evidence of original corner locations. In all instances where reference has been made to such co-ordinates in land surveys, the scale, sea level, and grid factors must also be stated for the survey lines used in computing ground distances and areas.

Nothing in this chapter shall be construed to require a purchaser or mortgagee of real property to rely wholly on a land description, any part of which depends exclusively upon either Ohio co-ordinate system.

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Ohio Revised Code157.09 Distances, bearings, and areas computed indirectly from co-ordinates

Distances, bearings, and areas computed indirectly from co-ordinates shall be considered acceptable measurement evidence for land and other surveys if such co-ordinates have been determined in accordance with sections 157.04, 157.07, and 157.08 of the Revised Code

The Error Piggy Bank

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Why introduce unnecessary error?

What errors are acceptable?

You be the Judge.

Don’t feed the Error Pig!

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We eliminate the errors we can by using due diligence in taking our measurements.

We keep our equipment in proper adjustment.

We stay conscious of the weather and input the proper atmospheric corrections in our data collectors and total stations to compensate for temperature and pressure.

We scale all of our jobs to ground coordinates to minimize the effects of the differences between the ellipsoid and ground.

Don’t feed the Error Pig!

Combined Scale Factors:a case study

Latitude Elevation Combined Scale Factor Distance variation in 1000' LocationN 40°-12'-55" 930' 0.99999483 999.99 Delaware SouthN 40°-26'-02" 946' 1.00004223 1000.04 Delaware/MarionN 40°-42'-09" 945' 1.00008586 1000.09 Marion/WyandotN 40°-59'-38" 956' 1.00010576 1000.11 Wyandot/SenecaN 41°-15'-19" 785' 1.00009271 1000.09 Seneca/SanduskyN 41°-27'-14" 574' 1.00006458 1000.06 Sandusky/OttawaN 41°-42'-00" 558' 1.00002343 1000.02 North Bass Island

Ohio North ZoneGrid to Ground Combined Scale Factor Calculations

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We got through the “WHY” now let’s focus on the “HOW”

Field Work: Setting ControlKnow your Path

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B.PrimaryProjectControlPrimary Project Control will govern the positioning for all ODOT projects. After establishing the coordinates for primary project control, ensure all survey work is adjusted relative to the established control monuments.

C.PrimaryProjectControlType

Primary Project Control consists of two available monument types and two positioning methods. Use one of the following monument types and positioning methods unless otherwise specified by the Department:

*Monument

Type Monument Controls **Project

Category ***Positioning

Methods A Horizontal &Vertical Major Static GNSS B Horizontal with a Separate Temporary

Benchmark Minor and Minimal

++Static GNSS or ODOT VRS

* If site geology or site conditions do not permit placement of the monument, contact the District Survey Operations Manager.

** Project Category is defined in the Project Development Process Manual.

*** Contact the District Survey Operations Manager if GNSS positioning is not feasible due to site conditions.

++ Use only one positioning method for project control on a single project. Do not combine Static GNSS and ODOT VRS for project control.


502.1 – 502.2.D

ODOT Type “A” Monuments

Setting Control

Set a minimum of (3) 8 inch concrete monuments that will survive the project

Benchmarks (elevations) established on the concrete monuments

Path 3 thru Path 5

Complex Projects

R/W involvement

Projects usually span longer time frames

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3/4” Rebar with 3-1/4” Aluminum Cap

5/8” Rebar with Plastic Cap

Benchmarks

Spike in Pole

Chiseled “X”

Square Cut

Setting Control

Set a minimum of (3) 30” pins that will survive the project

Existing control can be used if it meets the specifications

502.1 – 502.2.D

ODOT Type “B” Monuments

Path 1 thru Path 3

Simple Projects

Little or no R/W involvement

Projects usually completed in shorter time frames

Field Work: Measuring Control Points

Initial survey control is collected as grid coordinates in meters

Grid coordinates are the direct mathematical conversion from WGS 84 (Latitude, Longitude, Ellipsoid) to State Plane Coordinates.

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Depending on the size of the job and number of control points to be set, the horizontal positioning of the control normally only takes a few hours.

Leveling is typically performed on the control points to establish precise elevations.

We can also start our topographic mapping at this time (before control is formally established). As long as the control points are processed and entered into a Trimble Business Center project as Survey Control before the data collector files are imported, the data automatically adjusts to the control points.

Field Work: Measuring Control PointsType “A” Monuments

F.StaticGNSSDataCollection

Collect a minimum of 3 sessions of static GNSS data consisting of at least 4 hours per session for each primary project control monument. Ensure the survey equipment is removed and reinstalled over the monument between sessions. Ensure proper GNSS survey planning to achieve the required data quality as outlined in this specification. Consider the following when planning the GNSS survey: positional dilution of precision (PDOP), number of satellites, mask angle, collection rate, multipath, solar activity, etcetera.

G.StaticGNSSDataProcessing

Process the collected data to determine the Northing, Easting, and Elevation (Orthometric Height) for each session using National Geodetic Survey‟s OPUS (Online Positioning User Service). Use the rapid or precise ephemeris only. Ensure the correct antenna height, make, and model are utilized. Use the same three base stations when processing a primary project control point in OPUS. The user must manually select the base stations to be used in the OPUS processing.

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Field Work: Measuring Control PointsType “B” Monuments

H.ODOTVRSDataCollection

Collect the Northing, Easting, and Elevation coordinates using 5 second observations at a 1 second epoch rate. Collect a minimum of 5 observations for each project control monument. Note: More than 5 observations may be required to meet the minimum RMSE requirements specified below. Ensure the survey equipment is removed and reinstalled over the monument between sessions. Consider the following when planning and performing VRS surveys: positional dilution of precision (PDOP), number of satellites, mask angle, multipath, solar activity, etcetera.


Eliminate centering error

Take (4) shots, rotating the rod 90 degrees after each observation

Eliminate bad initializations

Physically break initialization between sets by turning the antenna upside-down or covering the antenna

Eliminate repeat site visits

(3) sets or (12) observations generally provides enough data to satisfy the RMSE requirements

502.1 – 502.2.D502.2.E – 502.2.H

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VERTICAL CONTROL

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Field Work: Leveling

502.4.A – 502.4.C

GPS does not have a strong vertical component

Leveling is used to establish precise elevations on all control points and benchmarks

One project control point is held for elevation, remaining control points and benchmarks are leveled from there

Processing502.1 – 502.2.D502.2.E – 502.2.H502.2.I - 502.2.M

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Processing

J.PrimaryProjectControlMonumentHorizontalCoordinatesThe Northing and Easting primary project control monument coordinates are determined by taking the average of each coordinate component from the OPUS or ODOT VRS solutions that meet the RMSE requirements as specified in Section 502.2 I.

K.PrimaryProjectControlMonumentVerticalCoordinatesEstablish the elevations of primary project control monuments or their associated temporary bench marks by differential leveling. Refer to section 502.4 for leveling procedures. Differential leveling for primary project control monuments and temporary benchmarks will originate from, and close on, the primary project control monument closest to the center of the project.

Hold the elevation calculated from the vertical component of the OPUS or ODOT VRS solutions for theprimary project control monument closest to the center of the project. Ensure the elevations for the primarycontrol monument meet the RMSE requirements as specified in Section 502.2 I. As a check, compare theleveled elevations to the GNSS determined elevations from Section 502.2 I. Highlight any differences thatexceed 0.10 U.S. Survey Foot and contact the District Survey Operations Manager immediately to determinea course of action prior to performing any additional work.

Processing

L.SecondaryandTemporaryProjectControlSecondary and Temporary project control for surveying or construction purposes are to be positioned relative to the primary project control. Establish a monument type sufficient to ensure stability for the anticipated duration of project or task to be performed. Establish secondary and temporary project control at an accuracy to ensure conformance to the project plans.

M.ProjectScaleFactorIf a project scale factor is required, use the following method for establishing the combined scale factor:

1. If Static GNSS is used to determine the positions for primary project control monuments, use the average of the OPUS calculated combined scale factors for the monument closest to the center of the project. Ensure the scale factor is calculated from OPUS solutions that meet the RMSE requirements. Scale the project about the origin of the coordinate system (0,0).

If VRS is used to position primary project control monuments, perform a 20 minute static observation on the monument closest to the center of the project. Submit the static session to OPUS-RS to obtain the combined scale factor. Scale the project about the origin of the coordinate system (0,0) using the combined scale factor. Ensure coordinates and elevations ob

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Checking the MappingClass I and Class II Planimetric Features“The Mapping” Planimetric Features- Existing 2 dimensional features collected with

traditional ground surveying, RTK, or Photogrammetry for use in engineering projects.

Planimetric Check Points- 2 dimensional positions that are obtained independently of the planimetric data collection. Use traditional or RTK survey methods for collecting this data.

Planimetric Accuracy Class- The required horizontal accuracy for all existing planimetric features in the mapping. The mapping is assigned an accuracy class by the District Survey Operations Manager.

Checking the MappingClass I and Class II Horizontal Accuracy Requirements

Simply put: if the product is being used to build something the data should be Class I

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Checking the MappingClass I and II Features (Examples)

Checking the Mapping

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Survey Points- 3 Dimensional positions collected with traditional ground surveying, RTK, Static GNSS, Photogrammetry, or Light Detection and Ranging (LiDAR). Points are used to create the Triangulated Irregular Network (TIN)

Check Points- 3 dimensional positions obtained independently of Survey points by traditional ground surveying, RTK, or Static GNSS. Check points are used to verify the vertical accuracy of the TIN

Dz- Mathematical difference between the elevations from the Check Points and elevations produced from the TIN at the same horizontal location.

Root Mean Square Error (RMSE)- Mathematical calculation that is used to describe the vertical mapping accuracy encompassing both random and systematic errors.

DTM Accuracy Class- A specific area within the mapping limits that has an assigned maximum allowable Dz and RMSE. The number of areas and the DTM accuracy class for each area is assigned by the District Survey Operations Manager.

Checking the DTM or Digital Terrain Model “The Contours”

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Checking the DTM or Digital Terrain Model “The Contours”


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Deliverables502.1 – 502.2.D502.2.E – 502.2.H502.2.I - 502.2.M502.2.N

Furnish the following deliverables:

1. Surveyor’s Certification Statement. A standard form is included in Appendix F. 2. A table that includes primary project control coordinates and azimuth mark

coordinates. Include the following in the table: a. Point Number b. Point Description c. Monument Type d. Positioning Method e. Grid Coordinates

a. Northing (meters) b. Easting (meters)

f. If applicable, Scaled Coordinates a. Northing (U.S. survey feet) b. Easting (U.S. survey feet)

g. If applicable, the Project Combined Scale Factor and associated monument h. Type A primary project control orthometric heights (U.S. survey feet) i. Temporary Benchmark number, description, and orthometric height listed with

each Type B primary control monument

1. NGS OPUS data sheets if used in the solutions 2. NGS OPUS-RS data sheets if used to obtain a scale factor 3. Statistical analysis for each primary project control monument and azimuth mark(s). (See

example, Appendix D) 4. Native survey data files in Trimble RAW or RINEX 2.0 format

Deliverables

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Deliverables

Surveyor’s Certification for Primary Project Control

I, (Surveyor’s Name) do hereby certify that the Primary Project Control for (name of project) were constructed and established in

accordance with the Ohio Department of Transportation’s Survey and Mapping Specifications, dated (last revision date) for a (major or

minor and minimal) project and meet the accuracy requirements as set forth therein. All observation data and RMSE calculations are on

file and available at the request of the Ohio Department of Transportation.

__________________________ __________

Signature Date Surveyor’s Seal

Surveyor’s Printed Name

And Registration Number

Every Project is Unique

Know the ODOT Survey and Mapping Specifications

Get a clearly defined Scope of Services from the District Planning and Engineering Department

Get in touch with the District Survey Operations Manager early in the project. They are there to help you.

Submit your Survey Quality Control report to the District as soon as you are done with the mapping. Make sure the Survey Operations Manager is included on the correspondence.

Being proactive and making sure you have the line of communication open with the Survey Operations Manager will save you a lot of head aches as the project progresses through design and Right-of-Way acquisition.our District’s Survey Operations Manager

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REMEMBER! YOUR MAPPING AND CONTROL IS THE FOUNDATION OF THE PROJECT.

IT IS IMPORTANT INFORMATION!

IT NEEDS TO BE CORRECT!

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