Arizona Geographic Information Council 2002 AGIC Conference

1
Arizona Geographic Information Council2002 AGIC
Conference
GIS without Geodesy is a FELONY!!
Dave Minkel, National Geodetic Survey NGS
Geodetic Advisor for Arizona Dave.Minkel_at_noaa.gov,
[phone]
2
Workshop Outline

• Datums
• Earth Model (a.k.a. Ellipsoid)
• Horizontal Datums
• Vertical Datums
• Projections
• Geodetic control
• Transformations
• Public Land Survey System (PLSS)
• And (If theres time left)
• GPS Data Services from NGS
• GPS Update
• Future of the geodetic network

3
The National Geodetic Survey- a brief overview -

• Formed in 1807 by President Jefferson
• Survey of the Coast (1807 - 1878)
• US Coast Geodetic Survey (1878 - 1970)
• Geodesy is the applied science that deals with
  the size and shape of the earth.
• Responsible for the establishment and maintenance
  of the National Spatial Reference System (NSRS)
• Geodetic Advisor program puts an NGS geodesist in
  cooperating States

4
ACRONYMS US
R
NAD 27
ITRF 97
GRS 80
WGS 84
NAVD 88
EGM 96
GEOID 99
NGVD 29
NAD 83
GEOID 96
5
DATUMS

• A set of constants specifying the coordinate
  system used for geodetic control, i.e., for
  calculating coordinates of points on the Earth.
• Specific geodetic datums are usually given
  distinctive names. (e.g., North American Datum of
  1983, European Datum of 1950, National Geodetic
  Vertical Datum of 1929)

6
HORIZONTAL DATUMS

• 8 Constants
• 3 specify the location of the origin of the
  coordinate system.
• 3 specify the orientation of the coordinate
  system.
• 2 specify the dimensions of the reference
  ellipsoid

7
VERTICAL DATUMS

• A set of fundamental elevations to which other
  elevations are referred.

8
Ellipsoid of RevolutionMathematical Model of the
Earth
N
b
a
S
a Semi major axis b Semi minor axis f
a-b Flattening a
9
UNITED STATESELLIPSOID DEFINITIONS
BESSEL 1841 a 6,377,397.155 m 1/f
299.1528128
CLARKE 1866 a 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
10
HORIZONTAL DATUMS

• BESSEL 1841 -------------- LOCAL ASTRO DATUMS
  (1816-1879)
• 
  NEW ENGLAND DATUM (1879-1901)
• 
  U.S. STANDARD DATUM (1901-1913)
• 
  NORTH AMERICAN DATUM (1913-1927)
• 
  NORTH AMERICAN DATUM OF 1927
• OLD
  HAWAIIAN DATUM
• CLARKE 1866 PUERTO RICO DATUM
• 
  ST. GEORGE ISLAND - ALASKA
• 
  ST. LAWRENCE ISLAND - ALASKA
• 
  ST. PAUL ISLAND - ALASKA
• 
  AMERICAN SAMOA 1962
• 
  GUAM 1963
• GRS80 ----------- NORTH AMERICAN DATUM OF
  1983
• 
  (As of June 14, 1989)

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THE GEOID AND TWO ELLIPSOIDS

CLARKE 1866
GRS80 or WGS84
North America
Earth Mass Center
Approximately 236 meters
GEOID
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3D Coordinate System (NAD 83 WGS 84)Geodetic
(Geographic) Coordinates
GRS80 or WGS84 Ellipsoid

Point (F,?)
Earth Mass Center
Latitude (F)
Semi-Minor Axis
Semi-Major Axis
Prime Meridian (Greenwich, England) 0o Longitude
Equator
Longitude (?)
13
3D Coordinate Systems (NAD 83, ITRF, WGS
84)Earth-Centered Earth-fixed (ECEF)
Z Axis (parallel to axis of rotation)

Point in Arizona (-X1, -Y1, Z)
GRS80-WGS84
Z1
Point (X1, Y1, Z1)
Z1
-Y1
Earth Mass Center
Y1
Y Axis (270o W)
-X1
X1
GEOID
X Axis (Prime Meridian)
14
COMPARISON OF DATUM ELEMENTS

• 
  NAD 27 NAD 83
• ELLIPSOID CLARKE 1866 GRS80
• a 6,378,206.4 m
  a 6,378,137. M
• 1/f 294.9786982
  1/f 298.257222101
• DATUM POINT Triangulation
  Station
  NONE
• MEADES RANCH, KANSAS EARTH MASS
  CENTER
• ADJUSTMENT 25k
  STATIONS 250k STATIONS
• Several Hundred Base Lines
  Appox. 30k EDMI Base Lines
• Several Hundred Astro Azimuths
  5k Astro Azimuths
• 
  Doppler Point Positions
• 
  VLBI Vectors
• BEST FITTING North
  America
  World-Wide

15
NAD 27 and NAD 83
Can you say Metadata?
16
NAD83 is properly called NAD83 (1986) or NAD83
(86). In Arizona, NAD83 (HPGN), which is
ESRI-speak, is actually NAD83 (1992). The date
will change with the state whose data you are
looking at (e.g. UTAHs NAD83 (HPGN) is NAD83
(1994). NAD83 tells you the datum of the
coordinates, and the date tells you the year of
the adjustment (the coordinate set). Beginning
in 2005, NGS will readjust all GPS stations in
the network. At the end of that effort all
stations will be NAD83 (NSRS) or something
similar.
17
ITRF

• International Terrestrial Reference Frame
• Defined by International Earth Rotation Service
  (late 1980s)
• Uses GRS80 Ellipsoid
• Has an epoch tag (ITRF88, ITRF03, etc.)
• 508 stations in 290 globally distributed sites
• GPS, VLBI, SLR, LLR, and DORIS
• Station velocities due to crustal motion are
  included
• Basis of all modern, high-accuracy networks
• Approximately (few centimeters) the same as WGS84

18
WORLD GEODETIC SYSTEM 1984TR8350.2 World
Geodetic System 1984 - Its Definition
andRelationships with Local Geodetic
Systems(http//www.nima.mil/GandG/pubs.html)
DATUM WGS 84 RELEASED - SEPTEMBER 1987 BASED ON
OBSERVATIONS AT MORE THAN 1900 DOPPLER STATIONS
DATUM WGS 84(G730) 5 USAF GPS Tracking
Stations 5 DMA Evaluation Stations Datum
redefined with respect to the International
Terrestrial Reference Frame of 1992 (ITRF92) /-
20 cm in each component (Proceedings of the ION
GPS-94 pgs 285-292)
DATUM WGS 84(G873) 5 USAF GPS Tracking
Stations 7 NIMA Evaluation Stations Datum
redefined with respect to the International
Terrestrial Reference Frame of 1994 (ITRF94) /-
10 cm in each component (Proceedings of the ION
GPS-97 pgs 841-850)
19
I NEED TO TRANSFORMBETWEEN WGS 84 AND NAD 83
Federal Register Notice Vol. 60, No. 157, August
15, 1995, pg. 42146 Use of NAD 83/WGS 84 Datum
Tag on Mapping Products
20
MY SOFTWARE SAYS IM WORKING IN WGS-84
Unless you doing autonomous positioning (point
positioning /- 6-10 meters) youre probably NOT
in WGS-84
Project tied to WGS-84 control points obtained
from the Defense Department -- Good Luck!
Youre really working in the same reference frame
as your control points -- NAD 83?
21
ELLIPSOID - GEOID RELATIONSHIP
H Orthometric Height / Elevation (NAVD 88)

h Ellipsoidal Height (NAD 83)
GPS gives you this, not elevation.
N Geoid Height (GEOID 03)

H h - N
H
TOPOGRAPHIC SURFACE
h
N
GEOID03
Geoid
Ellipsoid GRS80
22
VERTICAL DATUMS

• MEAN SEA LEVEL DATUM OF 1929
• NATIONAL GEODETIC VERTICAL DATUM OF 1929
• NGVD 29
• (As of July 2, 1973)
• NORTH AMERICAN VERTICAL DATUM OF 1988
• NAVD 88
• (As of June 24, 1993)

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COMPARISON OF VERTICAL DATUM ELEMENTS

• 
  NGVD 29
  NAVD 88
• DATUM DEFINITION 26 TIDE GAUGES
  FATHERS POINT/RIMOUSKI
• 
  IN THE U.S. CANADA
  QUEBEC, CANADA
• BENCH MARKS 100,000
  450,000
• LEVELING (Km)
  102,724
  1,001,500
• GEOID FITTING Distorted to Fit
  MSL Gauges Best Continental
  Model

24
NGVD 29 and NAVD 88
Can you say Metadata?
25
VERTCON (NGVD29 lt-gt NAVD 88)

• Similar to NADCON in operation
• Uses gridded data set
• Available as PC program or on-line (Geodetic Tool
  Kit)
• PC version allows file input
• Based on 381,833 datum differences
• Only for CONUS (48 conterminous)
• Accurate to approx. 4 cm (2 sigma)
• Does NOT replace differential leveling

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Projections
Arizona Geographic Information Council2002 AGIC
Conference
27
Projections

• Geodesy is surveying when you cant pretend the
  earth is flat J. Ross Mackay, NGS State Advisor,
  KY
• Conversely, a projection is an attempt to
  represent points on the curved surface of the
  Earth, as defined by a datum, on a flat sheet of
  paper (or a monitor). A projections mapping
  equations are used to transform the 3-D positions
  (Lat., Long., Height) to 2-D positions (X,Y).

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TANGENT PLANE COORDINATE SYSTEM
Tangent Plane Single Point of Contact
29
LAMBERT CONFROMAL CONICWITH 2 STANDARD PARALLELS
Grid Scale Factor
SCALE gt 1
Nn
SCALE EXACT
STANDARD PARALLELS
SCALE lt 1
Ns
SCALE EXACT
SCALE gt 1
80
CENTRAL MERIDIAN
30
TRANSVERSE MERCATOR
SCALE lt 1
SCALE gt 1
SCALE EXACT
SCALE EXACT
SCALE gt 1
80
CENTRAL MERIDIAN
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PLANE COORDINATE SYSTEMS

• STATE PLANE AND UNIVERSIAL TRANSVERSE MERCATOR
  GRID COORDINATES ARE A DIRECT MATHEMATICAL
  CONVERSION FROM LATITUDE AND LONGITUDE TO A
  CARTESIAN NORTHING AND EASTING (Y X) COORDINATE
  SYSTEM, AND MUST MAINTAIN THE SAME DATUM TAG
  e.g. NAD 83(1996) AS THE LATITUDE AND LONGITUDE

NATIONAL OCEAN SERVICE
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UNIVERSAL TRANSVERSE MERCATOR (UTM)

• http//www.nima.mil/GandG/pubs.html
• The Universal Grids Universal Transverse
  Mercator (UTM) and Universal
  Polar Stereographic (UPS) - TM8358.2
• Transverse Mercator Projection
• Zones 6o Longitude World-Wide
• Northing Origin (0 meters- Northern Hemisphere)
  at the Equator
• Easting Origin (500,000 meters) at Central
  Meridian of Each Zone
• NAD 27 and NAD 83 both defined in meters
• NAD 27 to NAD 83 shift 200-225 meters for U.S.

NATIONAL OCEAN SERVICE
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US National Grid (USNG)

• Grid Zone Designation - The U.S. is divided
  into 6-degree longitudinal zones designated by a
  number and 8-degree latitudinal bands designated
  by a letter. Each area is given a unique
  alpha-numeric Grid Zone Designator (GZD) (i.e.
  18S).
• Each GZD 6x8 degree area is covered by a
  specific scheme of 100,000-meter squares where
  each square is identified by two unique letters.
  (i.e. 18SUJ - Identifies a specific 100,000-meter
  square in the specified GZD).
• A point position within the 100,000-meter
  square shall be given by the UTM grid coordinates
  in terms of its Easting (E) and Northing (N). An
  equal number of digits shall be used for E and N
  the reading shall be from left with Easting first
  and then Northing.
• 18SUJ2306 - Locates a point with a precision of 1
  km
• 18SUJ2348306479 - Locates a point with a
  precision of 1 meter

NATIONAL OCEAN SERVICE
34
STATE PLANE COORDINATE SYSTEMS

• NOAA Manual NOS NGS - 5 State Plane Coordinate
  System of 1983 http//www.ngs.noaa.gov/PUBS_LIB/M
  anualNOSNGS5.pdf
• Lambert Conformal Conic and Transverse Mercator
  Projections
• International, State and County Boundaries
• NAD 27 - Coordinates in U.S. Survey Feet
• NAD 83 - Coordinates Metric w/State Defined Foot
  Conversion
• 1 Meter 3.280833333 U.S. Survey Feet
• 1 Meter 3.280839895 International Feet
• NAD 27 to NAD 83 VERY large Positional Shifts
• (approx. 37.9 miles westerly in Arizona)

35

• AZs SPC is a Transverse Mercator projection
• Zones defined by county lines
• Same zones as NAD 27
• Designed to maintain 110,000
• AZ W is 115,000
• NAD 83 AZ SPC uses International Foot
• NAD 27 used US Survey Foot
• Cannot tell foot unit by inspection
• Only 7 states use International Foot
• NAD 27 NAD 83 SP coordinates are
  significantly different on purpose
• Easting is much larger
• The relationship between all SPC systems is
  rigorously defined (you can get there from here)

36
111o 10' W
Origin 31o 00 N, 110o 10 W N 0.0 m, E
213,360.0 m
Central Meridian
37
Central Meridian
111o 55 W
Origin 31o 00 N 111o 55 W N 0.0 m, E 213,
360.0 m
38
Origin 31o 00 N 113o 45 W N 0.0 m E
213,360.0 m
Central Meridian
113o 45 W
Ramsey
39
COORDINATE CHANGES(STATE PLANE)

• STATION RAMSEY
• ARIZONA STATE PLANE COORDINATES (NAD 27/NAD 83
  (92))
• Northing Easting
  Converg Angle Scale Factor
• (NAD 27) 969,877.379 ft. 423,771.616
  ft. -0o 08 18.4 0.999939945
• (NAD 83) 295,628.663 m. 190,126.060 m.
  -0o 08 20.0 0.99993999
• (969,908.37 ft) (623,771.92
  ft)
• (969,910.31 ft) (623,773.16
  ft)
• (1.94)
  (1.24)
• Converted using U.S. Survey
  Foot, 1 M 3.2808333333 Ft.
• Converted using International
  Foot, 1 M 3.2808398501 Ft.

40
STATUS OF NAD 27 AND NAD 83 STATE PLANE
COORDINATE LEGISLATION - APRIL, 2000

• NO SPCS EXISTING NAD 27
  ENACTED NAD 83 SPC LEGISLATION LEGISLATION
  LEGISLATION
• (4) (3)
  
  (45)
• District of Columbia Alabama
  Alaska Maryland (S)
  Oklahoma (S)
• Hawaii Arkansas Arizona
  (I) Massachusetts (S) Oregon (I)
• Nebraska Illinois
  California (S) Michigan (I)
  Pennsylvania (S)
• Puerto Rico Colorado
  (S) Minnesota Rhode Island
• 
  
  Connecticut
  (S) Mississippi (S) South Carolina
  (I)
• I International Feet and Meters
  Delaware(S) Missouri
  South Dakota
• 1 m 3.280839895 feet Florida (S)
  Montana (I) Tennessee (S)
• S U.S. Survey Feet and Meters Georgia (S)
  Nevada Texas (S)
• 1 m 3.280833333 feet
  Idaho (S) New
  Hampshire Utah (I)
• Indiana (S) New
  Jersey Vermont
• 
  Iowa New Mexico (S)
  Virginia (S)
• 
  Kansas New York (S)
  Washington (S)
• 
  Kentucky (S) North Carolina (S)
  West Virginia
• 
  Louisiana North Dakota (I)
  Wisconsin (S)
• 
  Maine Ohio
  Wyoming

41
Datums Projections used in Arizona
Survey Data courtesy of Tom Elder, City of Phoenix
42
GROUND LEVEL COORDINATES

• I want State Plane Coordinates at ground.
• Ground level coordinates are NOT State Plane
  Coordinates!!!!! SPCs are defined on the
  ellipsoid, not at ground.

43
GROUND LEVEL COORDINATES
Distance (Grid) ? Distance (Ground)
Ground
Ellipsoid Height
Grid
44
GROUND LEVEL COORDINATESPROBLEMS

• PROJECTS DIFFICULT TO TIE TOGETHER
• CONFUSION OF COORDINATE SYSTEMS
• LACK OF DOCUMENTATION

45
Ground Level Coordinate Problem(s)

46
GROUND LEVEL COORDINATESHow do I fix them?

• Surveyor (data source) must provide explicit
  description of how ground coordinates were
  determined METADATA !!
• Divide the ground coordinates by the combined
  factor
• Combined factor scale factor X elevation factor
• Scale factor (combination of point scale factors)
• Elevation factor (20,906,000)/(20,906,000 H
  N)
• 20,960,000 m Mean earth radius
• H Orthometric Height (a.k.a. Elevation)
• N Geoid Height (Geoid 03)
• A common method to bring ground coordinates to
  grid, but not necessarily the right method
• Regionalized combined factor
• City of Scottsdale
• Explicitly specify the method of
  projection/conversion in contracts
• No Metadata No Hope (almost)

47
GROUND LEVEL COORDINATESWhy would I want them?

• Flagstaff, AZ (Flagstaff NCMN)
• Elevation 2168 m, Geoid Height -23 m
• Scale factor 0.99990812
• Elevation Factor 0.999897408
• Combined Factor 0.999805537
• Distortion
• In ppm Combined factor 1 195 ppm
• Proportional 15128
• 2000 m (grid) 2000.4 (ground)
• 5280 ft (grid) 5281.03 ft (ground)

48
Metadata for Positions/Coordinates

• METADATA IS DATA ABOUT DATA
• DATUM
• NAD 27, NAD 83(1986), NAD 83 (199X), NGVD29,
  NAVD88
• UNITS
• Meters, U.S. Survey Feet, International Feet,
  Chains, Rods, Pole
• ACCURACY
• A, B, 1st, 2nd, 3rd, 3cm, Scaled
• SOURCE
• Surveyor, Engineer, Digitized, Scanned
• Who dun it?

49
METADATA??
Horizontal Datum??
Plane Coordinate Zone ??
Units of Measure ??
How Accurate ??
50
An example of good Metadata everything is stated
AND its clear and explicit! This information is
found in the legend for the drawings associated
with the project.
51
Low DistortionProjections
Arizona Geographic Information Council2002 AGIC
Conference
52
A method for reducingmap projection distortion
in areas of significant topographic
relief(Presented at 2003 ACSM Annual
Conference)

• Michael L. Dennis, P.E.
• Shephard-Wesnitzer, Inc.
• Western Australian Centre for Geodesy
• Curtin University of Technology

53
Linear distortion at the ground

• Ratio of infinitesimal grid and ground lengths
  at a point
• Same in all directions for conformal projections
• Linear distortion, d, at a point on the ground
  is computed here as
• where
• k projection grid scale factor (w/respect to
  ellipsoid)
• h height of point above ellipsoid
• R ellipsoid radius
• Distortion expressed here in parts per million
  (ppm)

Source Michael Dennis, PE Shepard Wesnitzer
Inc.
54
Cartoon Distortion due to curvature
Source Michael Dennis, PE Shepard Wesnitzer
Inc.
55
Horizontal distortion of grid coordinates due to
Earth curvature
Source Michael Dennis, PE Shepard Wesnitzer
Inc.
56
Cartoon Distortion due to change in ellipsoidal
height
Source Michael Dennis, PE Shepard Wesnitzer
Inc.
57
Distortion of grid coordinates due to variation
in ground height
Source Michael Dennis, PE Shepard Wesnitzer
Inc.
58
Cartoon Sloped terrain with respect reference
ellipsoid
Source Michael Dennis, PE Shepard Wesnitzer
Inc.
59
Cartoon Datum transformation to reduce
distortion due to change in height
Source Michael Dennis, PE Shepard Wesnitzer
Inc.
60
Cartoon Sloped projection with reduced linear
distortion
Source Michael Dennis, PE Shepard Wesnitzer
Inc.
61
Datum transformation and projection computation
results
Source Michael Dennis, PE Shepard Wesnitzer
Inc.
62
Verde Valley projection, revisited
Source Michael Dennis, PE Shepard Wesnitzer
Inc.
63
Sloped projection showing 20 ppm distortion area
Source Michael Dennis, PE Shepard Wesnitzer
Inc.
64
Conclusions

• Method can substantially reduce linear
  distortion in areas of significant relief
• Useful for areas and projects where ground
  coordinates desired
• But limited to areas of more-or-less uniform
  topographic slope
• Relatively simple to implement
• Can be used with any type of projection
• Datum transformation can be hidden inside
  projection algorithm
• Only 2 numbers needed to define transformation
  (slopes north east)
• Does not restrict transferability of data
• Fully reversible Can obtain original reference
  geodetic coordinates
• Can then re-project coordinates using any other
  type of projection

Source Michael Dennis, PE Shepard Wesnitzer
Inc.
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Geodetic Control
Arizona Geographic Information Council2002 AGIC
Conference
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GEODETIC CONTROL

• NETWORK OF MONUMENTED POINTS
• PRECISELY MEASURED IN ACCORDANCE
• WITH STANDARD PROCEDURES
• MEET ACCURACY SPECIFICATIONS
• ADJUSTED TO FIT (or TIE) TOGETHER
• DOCUMENTED FOR MULTIPLE USE

67
Stainless steel rod driven to refusal
Poured in place concrete post
68
NATIONAL SPATIAL REFERENCE SYSTEM

• The National Spatial Reference System (NSRS) is
  that component of the National Spatial Data
  Infrastructure (NSDI) - http//www.fgdc.gov/nsdi/
  nsdi.html which contains all geodetic control
  contained in the National Geodetic Survey (NGS)
  Data Base. This includes A, B, First, Second
  and Third-Order horizontal and vertical control,
  Geoid models such as GEOID 03, precise GPS orbits
  and Continuously Operating Reference Stations
  (CORS), and the National Shoreline as observed
  by NGS as well as data submitted by other
  Federal, State, and local agencies, Academic
  Institutions and the private sector.

69
NATIONAL SPATIAL REFERENCE SYSTEM

• ACCURATE -- cm accuracy on a global scale
• MULTIPURPOSE -- Supports Geodesy, Geophysics,
  Land Surveying, Navigation, Mapping, Charting and
  GIS activities
• ACTIVE -- Accessible through Continuously
  Operating Reference Stations (CORS) and derived
  products (e.g. OPUS)
• INTEGRATED -- Related to International services
  and standards (e.g. International Earth Rotation
  Service, International
• GPS Service etc.)

70
NAD 83 NETWORK PROBLEMS

• NOT GPSABLE

POOR STATION ACCESSIBILITY
IRREGULAR STATION SPACING
POSITIONAL ACCURACY
71
HIGH ACCURACY REFERENCE NETWORKS

• GPSABLE
• Clear Horizons for Satellite Signal Acquisition
• EASY ACCESSIBILITY
• Few Special Vehicle or Property Entrance
  Requirements
• REGULARLY SPACED
• Always within 20-100 Km
• HIGH HORIZONTAL ACCURACY
• A-Order (5 mm 110,000,000
• B-Order (8mm 11,000,000)
• HARN, HPGN, FBN
• Different acronyms for the same thing

72
HIGH ACCURACY REFERENCE NETWORKS
73
IMPROVING POSITIONAL ACCURACY

• TIME NETWORK
  LOCAL
• NETWORK SPAN ACCURACY ACCURACY
• NAD 27 1927-1986
  10 Meters First-Order (1 part
  in 0.1 million)
• 
  
• NAD 83 1986-1990
  1 Meter First-Order(1
  part in 0.1 million)
• HARN 1987-1997
  0.1 Meter B-Order(1
  part in 1 million)
• 
  
  A-Order (1 part in 10 million)
• CORS 1994 -
  0.02 Meter -
  Horizontal
• 
  0.04
  Meter - Ellipsoid Height
• 
  

74
GEODETIC CONTROL DATA SHEET
1 National Geodetic Survey, Retrieval
Date JULY 9, 2002 DV1145

DV1145 FBN - This is a Federal Base
Network Control Station. DV1145 DESIGNATION -
RAMSEY DV1145 PID - DV1145 DV1145
STATE/COUNTY- AZ/LA PAZ DV1145 USGS QUAD -
PLOMOSA PASS (1990) DV1145 DV1145
CURRENT SURVEY CONTROL DV1145
__________________________________________________
_________________ DV1145 NAD 83(1992)- 33 39
56.95619(N) 114 00 01.91029(W) ADJUSTED
DV1145 NAVD 88 - 475.040 (meters)
1558.53 (feet) ADJUSTED DV1145
__________________________________________________
_________________ DV1145 X -
-2,161,551.447 (meters) COMP
DV1145 Y - -4,854,803.033 (meters)
COMP DV1145 Z -
3,515,902.397 (meters) COMP
DV1145 LAPLACE CORR- 0.61 (seconds)
DEFLEC99 DV1145 ELLIP HEIGHT-
443.70 (meters) GPS
OBS DV1145 GEOID HEIGHT- -31.32
(meters) GEOID99 DV1145
DYNAMIC HT - 474.492 (meters) 1556.73
(feet) COMP DV1145 MODELED GRAV-
979,467.9 (mgal) NAVD 88
DV1145 DV1145 HORZ ORDER - A DV1145 VERT
ORDER - FIRST CLASS II DV1145 ELLP ORDER
- THIRD CLASS I
H h N 475.040 443.70 (-31.32) 475.040 ?
475.02

75
GEODETIC CONTROL DATA SHEET

DV1145SPC AZ W - 295,628.663
190,126.060 MT 0.99993999 -0 08 20.0
DV1145SPC AZ C - 297,539.454 20,094.843
MT 1.00036036 -1 09 20.0 DV1145UTM 11
- 3,729,141.759 778,123.802 MT 1.00055373
1 39 49.7 DV1145UTM 12 - 3,729,144.619
221,777.758 MT 1.00055441 -1 39 51.9
DV1145 DV1145! - Elev Factor x
Scale Factor Combined Factor DV1145!SPC AZ W
- 0.99993035 x 0.99993999
0.99987034 DV1145!SPC AZ C - 0.99993035 x
1.00036036 1.00029068 DV1145!UTM 11
- 0.99993035 x 1.00055373 1.00048404
DV1145!UTM 12 - 0.99993035 x
1.00055441 1.00048472 DV1145
DV1145-------------------------------------------
-------------------------- DV1145 PID
Reference Object Distance
Geod. Az DV1145
dddmmss.s
DV1145 DV1143 RAMSEY RM 1
7.630 METERS 01835 DV1145 DV1147
RAMSEY AZ MK
0680936.4 DV1145 DV1974 LOS ANGELES PHOENIX
AWY BCN 25 APPROX.10.0 KM 1563949.0
DV1145 DV1144 RAMSEY RM 2
11.039 METERS 16926 DV1145--------------
--------------------------------------------------
----- DV1145 DV1145
SUPERSEDED SURVEY CONTROL DV1145 DV1145 ELLIP
H (09/30/92) 443.72 (m)
GP( ) 2 1 DV1145 NAD 83(1986)- 33 39
56.95198(N) 114 00 01.91873(W) AD( ) 2
DV1145 NAD 27 - 33 39 56.84800(N) 113
59 59.12850(W) AD( ) 2 DV1145 NAVD 88
(09/30/92) 475.04 (m) 1558.5 (f)
LEVELING 3 DV1145 NGVD 29 (??/??/92)
474.334 (m) 1556.21 (f) ADJ UNCH 1 2
76
GEODETIC CONTROL DATA SHEET

• DV1145 HISTORY - Date Condition
  Report By
• DV1145 HISTORY - 1949 MONUMENTED
  CGS
• DV1145 HISTORY - 1962 GOOD
  CGS
• DV1145 HISTORY - 1962 GOOD
  NGS
• DV1145 HISTORY - 1965 GOOD
  CGS
• DV1145 HISTORY - 1971 GOOD
  USE
• DV1145 HISTORY - 1981 GOOD
  NGS
• DV1145 HISTORY - 1981 GOOD
  NGS
• DV1145 HISTORY - 1981 GOOD
  NGS
• DV1145 HISTORY - 1985 GOOD
  AZDT
• DV1145 HISTORY - 19920203 GOOD
  NGS
• DV1145 HISTORY - 19960306 GOOD
  CHANCE
• DV1145 HISTORY - 19981111 GOOD
  NGS
• DV1145 HISTORY - 19981117 GOOD
  AZ-013
• DV1145
• DV1145 STATION
  DESCRIPTION
• DV1145
• DV1145'DESCRIBED BY COAST AND GEODETIC SURVEY
  1949 (DHK)
• DV1145'STATION LOCATED ABOUT 17 MILES AIR LINE
  WEST OF HOPE, 13

77
GEODETIC CONTROL DATA SOURCES

• NGS web site www.ngs.noaa.gov/datasheet.html
• on-line search for control and generates data
  sheets (text search)
• SDTS (Spatial Data Transfer Standard) format for
  import of data into GIS software (very large
  files)
• Shapefiles coming soon
• State Cartographers website -
  http//sco.az.gov/ngs.htm
• DSWIN software data files (by county)
• used to search for control and generate data
  sheets (text search)
• used to generate text files for import into GIS
  software
• used to generate text files for import into GPS
  receivers
• Arizona GeoServer - sco.az.gov/website/geoserver
  /
• on-line search for control and generate data
  sheets with a GUI

78
NEW STANDARDS FOR GEODETIC CONTROL

• Two accuracy standards
• (http//fgdc.er.usgs.gov/standards/status/swgstat.
  html)
• local accuracy ------------- adjacent
  points
• network accuracy ---------- relative to CORS
• Numeric quantities, units in cm (or mm)
• Both are relative accuracy measures
• Do not use distance dependent expression
• Horizontal accuracies are radius of 2-D 95 error
  circle
• Ellipsoidal/Orthometric heights are 1-D (linear)
  95 error

79
Datum Transformations
Arizona Geographic Information Council2002 AGIC
Conference
80
DATUM TRANSFORMATIONS

• 1. WHAT DATUM ARE THE EXISTING COORDINATES ON?
• 2. WHAT DATUM DO I WANT THE NEW COORDINATES ON?
• 3. HOW LARGE A GEOGRAPHICAL AREA DO I WANT TO
  CONVERT AT ONE TIME?
• 4. HOW MANY POINTS ARE COMMON TO BOTH DATUMS?
• 5. WHAT IS THE DISTRIBUTION OF THE COMMON
  POINTS?
• 6. HOW ACCURATE ARE THE EXISTING COORDINATES?
• 0.1 Foot
• 1.0 Foot
• 10. Feet
• 7. HOW ACCURATE DO I WANT THE NEW COORDINATES?

81
DATUM TRANSFORMATION IDEAL METHOD

• SATISFIES ALL USERS REQUIREMENTS
• CAPABLE OF TRANSFORMING LARGE HOLDINGS OF
  COORDINATE DATA
• NEAR-REAL TIME APPLICATIONS
• SIMPLE - METHOD SHOULD NOT REQUIRE AN EXPERT OR
  EXPERT DECISIONS TO BE MADE
• ACCURATE

82
DATUM TRANSFORMATIONS

• MOLODENSKY
• Converts latitude, longitude and ellipsoidal
  height to X,Y,Z Earth-Centered Coordinates.
• Applies a 3-dimensional change in the origin (dX,
  dY,dZ)
• Applies a change in the size and shape of the
  reference ellipsoid
• Converts new X,Y,Z Earth-Centered Coordinates
  back to latitude, longitude and ellipsoidal
  height

83
DATUM TRANSFORMATIONS

• MOLODENSKY
• For continental regions accuracy can be /- 8
  to 10 meters
• Does not model network distortions very well.
• Assumes heights in both systems are ellipsoidal
  (NAD 27 did not have ellipsoidal heights).

84
MOLODENSKY TRANSFORMATION
(http//www.nima.mil/GandG/pubs.html)
85
NADCON

• DESIGNED TO SATISFY THE MAJORITY OF THE IDEAL
  METHOD DESIGN AND IS DEFINED AS THE NATIONAL
  STANDARD.
• DESIGN CRITERIA
• Relies only on NGS archived data existing in both
  NAD 27 and NAD 83
• Not tied to NGS Data Base
• Provides consistent results, both forward and
  inverse
• Fast
• Small - Fits on a PC
• Accurate
• 15 cm (1 sigma) in Conterminous U.S. NAD 27 -
  NAD 83 (1986)
• 5 cm (1 sigma) per State/Region NAD 83 (1986) -
  HARN

Federal Register Notice Vol. 55, No. 155, August
10, 1990, pg. 32681 Notice to Adopt Standard
Method for Mathematical Horizontal Datum
Transformation
86
How does NADCON work?
N 0.12344 8 -1.87842
N 0.12249 8 -1.88963
Set of gridded NAD-27 network distortion factors
Positional error due To distortion
N 0.12423 8 -1.81246
N 0.12568 8 -1.83364
N 0.12449 8 -1.88905
NSRS survey station
N 0.12640 8 -1.85407
N 0.12499 8 -1.86543
87
COORDINATE COMPARISONNAD 27 to NAD 83(1992)

• ADJUSTED vs. TRANSFORMED
• Station RAMSEY
• LATITUDE
  LONGITUDE
• 33-39-56.95619 114-00-01.91029
  PUBLISHED (NAD83 (92))
• 33-39-57.01410
  114-00-01.92238 - MOLODENSKY
• 0
  .05791 0.01209
• 
  1.784 m 0.312 m
• THIS CORRESPONDS TO A POSITIONAL
• DIFFERENCE OF 1.811 m (5.94 ft)

88
COORDINATE COMPARISON NAD 27 to NAD
83(1992)

• NADCON
• http//www.ngs.noaa.gov/TOOLS/NADCON
• ADJUSTED vs. TRANSFORMED
• Station RAMSEY
• 
  LATITUDE LONGITUDE
• 
  33-39-56.95619 114-00-01.91029 - PUBLISHED
• 
  33-39-56.95626 114-00-01.90498 - NADCON
• 
  .0007 .00531
• 
  0.002 m 0.137 m
• THIS CORRESPONDS TO A POSITIONAL
• DIFFERENCE OF 0.137 m (0.45 ft)

89
COORDINATE COMPARISONNAD 27 to NAD 83(1996)

• ADJUSTED vs. TRANSFORMED
• Station RED STONE
• LATITUDE
  LONGITUDE
• 44-28-13.93221
  073-11-46.77900 - PUBLISHED
• 44-28-13.75032
  073-11-46.60413 - MOLODENSKY
• 
  .18189 .17487
• 
  5.614 m 3.865 m
• THIS CORRESPONDS TO A POSITIONAL
• DIFFERENCE OF 6.816 m (22.36 ft)

90
COORDINATE COMPARISON NAD 27 to NAD
83(1996)

• NADCON
• ADJUSTED vs. TRANSFORMED
• Station RED STONE
• 
  LATITUDE LONGITUDE
• 44-28-13.93221
  073-11-46.77900 - PUBLISHED
• 44-28-13.93057
  073-11-46.77912 - NADCON
• 
  .00164 .00012
• 
  0.051 m 0.003 m
• THIS CORRESPONDS TO A POSITIONAL
• DIFFERENCE OF 0.051m (0.17 ft)

91
GPS Positions What datum are they on?

• Autonomous GPS
• - WGS84 (almost ITRF)
• US Coast Guard DGPS (a.k.a. beacon)
• - NAD83
• FAA WAAS DGPS
• - ITRF (200?)
• Differentially corrected GPS
• - What Datum is the reference station on?

92
Public Land Survey System (PLSS)
Arizona Geographic Information Council2002 AGIC
Conference
93
Public Land Survey System

• A rectangular coordinate system based on a
  somewhat arbitrary point (Initial Point)
• Did not have geographic positions as part of the
  system
• A system to support land ownership or conveyance
  not mapping
• Depiction on USGS quads may or may not be based
  on field verification
• ALRIS source is digitized USGS Quads

94
Public Land Survey SystemGeographic Coordinate
Data Base (GCDB)

• Maintained by BLM on a state by state basis
• Current lack of national policy
• Might be on NAD 27 or NAD 83
• NOT a legal depiction of the corner location
• Average of all available positions
• Available at www.blm.gov/gcdb/

95
PLSS corner accuracy
Position comparison courtesy of Tim Smothers,
City of Peoria
96
AZ/CA Boundary Project Yuma Area
97
GPS Data Sources and Services from NGS
Arizona Geographic Information Council2002 AGIC
Conference
98
Geodetic Tool Kit

www.ngs.noaa.gov/TOOLS/
99
CONTINUOUSLY OPERATING REFERENCE STATIONS (CORS)

• Variety of Geodetic Quality Dual-Frequency
• Antennas and Receivers
• Allen-Osborne
• (SNR 8000 SNR 12 ACT)
• Ashtech
• (UZ-12, Z-XII3)
• Leica
• (SR9500 CRS1000, LEIAT5, RS500)
• Trimble
• (4000SS, 4700, 5700)

CHL1 - CAPE HENLOPEN, DE
100
(No Transcript)
101
CONTINUOUSLY OPERATING REFERENCE STATIONS (CORS)

• Some stations broadcast real-time correctors
• 1- 5 - 15 30 sec. post-process carrier phase
  observations
• Free access via Internet (RINEX-2 Format)
• More than 285 Station National Network

102
CONTINUOUSLY OPERATING REFERENCE STATIONS (CORS)

• NGS PROVIDES
• Reference Site Survey Monumentation
• Horizontal and Vertical NSRS Connections
• NAD 83, ITRF94, ITRF96, ITRF97, ITRF00
  Coordinates
• Network Data Collection - Hourly Daily
• Daily 3D Network Integrity Adjustment
• Public Data Distribution - Internet
• (http//www.ngs.noaa.gov/CORS/cors-data.html)
• 7 Year On-Line Data Holding

103
(No Transcript)
104
(No Transcript)
105
(No Transcript)
106
CORS DATA SHEET

• ITRF 00 NAVAL STATION NEW
  (NPRI), RHODE ISLAND Retrieved from NGS
  DataBase on 04/06/02 at 181130.
  __________________________________________________
  __________________________
  
  Antenna Reference Point(ARP)
  NAVAL STATION NEW CORS ARP
  --------------------------------------------------
  ------
  PID AI3285
  
  
  
  ITRF00 POSITION (EPOCH 1997.0)
  Computed
  in Aug. 2001 using every third day of data
  through 2000. X 1531392.471
  m latitude 41 30 35.44671 N
  Y -4531474.016 m longitude
  071 19 39.12747 W Z
  4204982.604 m ellipsoid height -13.015 m
  
  
  ITRF00 VELOCITY
  Predicted with
  HTDP_2.5 in Aug. 2001.
  VX -0.0165 m/yr
  northward 0.0044 m/yr
  VY -0.0025 m/yr eastward
  -0.0164 m/yr VZ
  0.0033 m/yr upward 0.0000 m/yr
  

107
CORS DATA SHEET

• NAD 83
• 
  NAD_83 POSITION
  (EPOCH 2002.0)
  Transformed from ITRF00 (epoch
  1997.0) position in Mar. 2002.
  X 1531393.023 m latitude 41 30
  35.41588 N Y
  -4531475.481 m longitude 071 19 39.12515
  W Z 4204982.718 m
  ellipsoid height -11.768 m
  
  NAD_83 VELOCITY
  
  Transformed from ITRF00 velocity in
  Mar. 2002. VX
  0.0005 m/yr northward -0.0014 m/yr
  VY -0.0006 m/yr
  eastward 0.0003 m/yr
  VZ -0.0012 m/yr upward
  -0.0002 m/yr
  _______________________________________________
  _____________________________

108
OPUS WHAT IS IT?

• On-line Positioning User Service
• Provides GPS users faster easier access to the
  National Spatial Reference System (NSRS)

109
OPUS What Do I need?

• Dual Frequency GPS (carrier phase) data
• Resource-grade GPS unit probably NOT suitable
• Stationary antenna (no kinematic data)
• Single station no networks
• Data rates of 1, 2, 3, 5, 6, 10, 15 or 30
  seconds
• At least 2 hours of GPS data
• RINEX generator (software)
• Converts GPS data from manufacturers format to
  industry standard format
• TEQC free from UNAVCO
• http//www.unavco.ucar.edu/data_support/softwa
  re/translation/translation.html

110
OPUS How do I use it?

• Go to OPUS web page www.ngs.noaa.gov/OPUS
• Enter your email address
• Use browse feature to select RINEX file on your
  computer
• Select antenna type from menu
• Enter antenna height in meters
• Option to select State Plane Zone
• Click UPLOAD
• Check your email in a few minutes

111
OPUS What do I get?
REF FRAME NAD83(CORS96)(EPOCH2002.0000)
ITRF97 (EPOCH2000.2843) X
-1933229.787(m) 0.006(m)
-1933230.343(m) 0.110(m)
Y -5043636.636(m) 0.022(m)
-5043635.169(m)
0.192(m) Z 3381904.220(m)
0.038(m)
3381904.084(m) 0.151(m) LAT 32
13 28.02620 0.023(m)
32 13 28.04274 0.011(m) E
LON 249 1 41.28058 0.012(m)
249 1 41.24070
0.040(m) W LON 110 58 18.71942
0.012(m) 110 58
18.75930 0.040(m) EL HGT
734.110(m) 0.036(m)
733.047(m) 0.265(m) ORTHO
HGT 763.270(m) 0.044(m) Geoid99
NAVD88 UTM Zone 12
SPC Zone
202(AZ) NORTHING 3565315.261(m)
NORTHING 136145.249(m)
EASTING 502650.865(m)
EASTING 302411.814(m)
112
GPS Update Whats upfor the Future?
Arizona Geographic Information Council2002 AGIC
Conference
113
Autonomous Positioning Before May 1, 2000
25-100 m
HORIZONTAL 100 meters
VERTICAL 156 meters
1996 Federal Radionavigation Plan Section A2-1,
Part B http//www.navcen.uscg.mil/policy/frp1996

• C/A Code on L1
• Selective Availability

114
Standalone Positioning Since May 1, 2000
6-11 m

• C/A Code on L1
• No Selective Availability

115
Standalone Positioning By 2011
Better resistance to interference
1-3 m

• C/A Code on L1
• C/A Code on L2
• New Code on L5

116
GLOBAL POSITIONING SYSTEM

• GPS BLOCK III
• Potential Future Developments
• http//206.65.196.30/gps/issues/dotgpspressrelease
  s.htm
• 30 - 32 satellites
• Second and Third Civil Frequency
• (1227.60 MHZ 1176.45 MHZ)
• More Robust Signal Transmissions
• Real-Time Unaugmented 1 Meter Accuracy
• Initial Launches 2005
• Complete Replacements 2011

117
GLOBAL NAVIGATION SATELLITE SYSTEMS(GNSS)

• POTENTIAL FUTURE DEVELOPMENTS
• (2005 - 2011)
• GPS MODERNIZATION - BLOCK III
• GLONASS ENHANCEMENTS (K M)
• EUROPEAN UNION - GALILEO
• 80 Satellites
• Second and Third Civil Frequency - GPS
• No Signal Encryption - GLONASS GALILEO
• More Robust Signal Transmissions
• Real-Time Unaugmented 1 Meter (or better!)
  Accuracy

118
The NETWORK Whats upfor the Future?
Arizona Geographic Information Council2002 AGIC
Conference
119
NAD 83 READJUSTMENT

• HARN COMPLETION - SEPTEMBER 1997
• (Indiana)
• GPS HEIGHT MODERNIZATION OBSERVATIONS
• (1997 - 2003)
• (http//www.ngs.noaa.gov/initiatives/height_modern
  ization.shtml
• COMPLETE GPS NAD 83 3-D ADJUSTMENT
• (http//www.ngs.noaa.gov/initiatives/new_reference
  .shtml)
• (2004-05)
• REMOVAL OF SMALL REGIONAL DISTORTIONS
• (3 - 6 CM)
• UNIFORM COORDINATE TAG
• NAD 83 (NSRS)

120
NAD 83 READJUSTMENT
121
NAD 83 READJUSTMENT

• ONLY GPS DATA
• CONTINUOUSLY OPERATING REFERENCE STATIONS
• FEDERAL BASE NETWORK
• COOPERATIVE BASE NETWORK
• AIRPORT SURVEYS
• USER DENSIFICATION NETWORK
• SPECIAL SURVEYS

122
GPS NETWORKS TO SUPPORT GIS CLASSICAL
123
GPS NETWORKS TO SUPPORT GIS 21st CENTURY
124
CLASSICAL GPS NETWORKS

• PROS
• Monumentation usually established in only 1 or 2
  GPS survey campaigns
• Complete coverage
• No time lag for users access to control
• CONS
• Large initial cost
• Continual network maintenance
• Monumentation destroyed or disturbed before
  theyre used
• System unfamiliar to non-surveyors
• Less efficient use of GPS receivers

125
CONTEMPORARY GPS NETWORKS

• PROS
• Minimal permanent monumentation
• Project control established when and where needed
• Costs spread over time
• More user friendly to a wider range of spatial
  data users
• More efficient use of GPS receivers
• CONS
• Qualified staff to coordinate and administer user
  requests
• Time lag to establish project control

126
GPS NETWORKS TO SUPPORT GIS

• GPS SURVEY DATA
• BLUE - BOOK SUBMISSION OF DATA FOR
• INCLUSION IN NSRS
• OR
• DATA MAINTAINED AT THE LOCAL LEVEL

127
GPS NETWORKS TO SUPPORT GISBLUE-BOOK

• PROS
• DATA MAINTAINED IN NSRS IN PERPETUTITY
• UNIVERSAL DATA ACCESS VIA NGS WEB SITE
• GOOD HOUSEKEEPING SEAL OF APPROVAL
• CONS
• INCREASED INITIAL COST (15 - 20)
• SLIGHT INCREASE IN INITIAL DATA PROCESSING TIME

128
GPS NETWORKS TO SUPPORT GISLOCAL MAINTENANCE

• PROS
• DECREASED INITIAL SURVEY COSTS
• LOCAL CONTROL OF ALL DATA
• CONS
• READJUSTMENTS TO FUTURE REFERENCE FRAME CHANGES
  MUST BE DONE AT THE LOCAL LEVEL
• DATA MAY BE DIFFICULT TO LOCATE FOR NON-LOCALS
• A.R.S. 33-137 REQUIRES PUBLISHING DATA

129
NATIONAL GEODETIC SURVEY
dave.minkel_at_noaa.gov 602-542-1569

• INFORMATION CENTER
• [phone]
• info_center_at_ngs.noaa.gov

WEB SITE http//www.ngs.noaa.gov