cayapan - wgs84-prs92

Charisma Victoria D. CayapanBasics on Geomatics and Satellite Orbits

Final Exam17 December 2010

A. Reference Systems in the PhilippinesB. The Philippine Triangulation Network PTNC. From PTN to the Philippine Reference System of 1992 PRS92

A. Types of Geodetic DatumsB. WGS84 and PRS92 Datum DifferencesC. Transformation TechniquesD. The Bursa‐Wolfe Seven Parameter Transformation

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•Location: Southeast Asia

•7,107 islands

•Geographical Extents:Latitude: 4˚15’ N ‐ 21˚25’ NLongitude: 112˚15’E ‐ 127˚ E

• Total land area: 300,000 km2

Luzon DatumLuzon Datum of 1911

Triangulation Network of the Philippines

Philippine Reference System of 1992Modified Luzon Datum

PRS92 Geodetic Control Network

Luzon Datum of 1911•Reference ellipsoid:

• Clarke Spheroid of 1866• Semi‐major axis, a 6,378,206.4 • Semi‐minor axis, b 6,356,583.8 • Flattening, f 1/294.98

• Datum Origin:• Fort Balanacan, Marinduque Island

Latitude: 13˚33’41 NLongitude: 121˚52’03 E

• Reference direction from south :To station Baltasar is: α0 009° 12’ 37.000”

• Geoid‐spheroid separation 0

Philippine Triangulation Network•Established by the US Coast and GeodeticSurvey from 1901‐1942

•Network consisted of narrow chains ofquadrilaterals located mostly along the coastlines

Modified Luzon Datum•Retained original coordinates and orientationof origin

•Geoid‐Spheroid separation 0.34m

•PRS92 geodetic control network establishedusing GPS technology

•Transformation parameters relating the GPS datum to the local horizontal geodetic system

based on location/orientation of origin

•Regional/Local Geodetic Datum• Reference ellipsoid fits the surface of the

Earth on a certain region or locality• Origin of the coordinate system is the

tangent point of the reference ellipsoidand geoid

•Global Geocentric Geodetic Datum• Reference ellipsoid fits the shape of the

Earth globally• Origin of the coordinate system coincide

with the center of mass of the Earth

World Geodetic System of 1984 WGS84•Global geocentric geodetic datum•Reference Ellipsoid:

• WGS84 Ellipsoid • Semi‐major axis, a 6,378,137 • Semi‐minor axis, b 6,356,752.3142 Flattening, f 1/298.257223563

Philippine Reference System of 1992 PRS92•Local geodetic datum•Reference Ellipsoid:

• Clarke Spheroid of 1866

1. Seven Parameter Bursa‐Wolfe Transformation• Assumes linear distortion within the network• Uses 7 parameters translation, rotation, scale• Needs at least 3 points with coordinates in both datums and doing least squares

fit.2. Molodensky Transformation

• Uses 5 parameters 3 for datum shifts and 2 for differences in semi‐major axes and flattening

• Assumes internally consistent network• Limited accuracy

. Multiple Regression Equation MRE Transformation• Better fit for modelling non‐linear distortion creates surface of distortion• Appropriate for transforming continental size land areas• Not to be extrapolated outside of area of intended use large distortion over

short distances• Requires many points and very complex to derive

• Transformation involving three translations X0, Y0, and Z0 , three rotations Rx, Ry, and Rz and scale µ .

• The 3D rotation matrix describes the rotation of the coordinate system in order to become parallel to another coordinate system

Depends on:

•Number of common points used to derive the parameters redundancy for adjustment/refinement

•Geometric distribution of the common points well distributed over the whole coverage area

•Consistency of the network distortion within the network

Parameters WGS84 to PRS92 PRS92 to WGS84Translation X ΔX 127.62195 ‐127.62195Translation Y ΔY 67.24478 ‐67.24478Translation Z ΔZ 47.04305 ‐47.04305Rotation X Rx ‐3.067062 3.067062Rotation Y Ry 4.90291 ‐4.90291Rotation Z Rz 1.57790 ‐1.57790Scale Sc 1.06002 ‐1.06002

• Increasing trend is to shift from a local/regional geodetic datum to a geocentric geodetic datum or relate to one .

• Datum transformation defines the relationship between the two datums.

• Transformation parameters facilitate the data integration from one datum to another.

• Assessment of the PRS92 Geodetic Control Network and Development of Recommended Guidelines for Primary Geodetic Control, Tidal and Geopotential Surveys – Final Report. Research and Development in Support of the Implementation of the Philippine Reference System of 1992. Training Center for Applied Geodesy and Photogrammetry. University of the Philippines, 2009.

• The Philippine Geodetic Network. National Mapping and Resource Information Authority, 1992.

• World Geodetic System of 1984 – Its Definition and Relationships with Local Geodetic Systems. National Imagery and Mapping Agency Technical Report TR8350.2 , Third Edition, Amendment 1, 9 January 2000.

cayapan - wgs84-prs92

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