PRS92 Bonifacia Daet Sylvia Esperanza The Philippine Reference System of 1992 Bonifacia Daet Sylvia Esperanza

OUTLINE Introduction History Datum Quantities PRS92 Parameters Significance to Philippine Mapping On-going Programs From 1901 to 1911, the US Coast and Geodetic Survey established several small triangulation networks which had different origins. In 1911, these small networks were consolidated into the Luzon Datum and became the primary reference of all surveys in the Philippines.

National network of geodetic control points (GCPs) Philippines’ standard coordinate reference system for all survey and mapping activities National network of geodetic control points (GCPs) established using the Global Positioning System (GPS) Implemented in 1989-1992 through an Australian-assisted project - Natural Resources Management & Development Project (NRMDP) From 1901 to 1911, the US Coast and Geodetic Survey established several small triangulation networks which had different origins. In 1911, these small networks were consolidated into the Luzon Datum and became the primary reference of all surveys in the Philippines.

Philippine Triangulation Network (1901 to 1911) Why Do We Need PRS92? Philippine Triangulation Network Established in 1901-1911 by the US Coast and Geodetic Survey Narrow chains of 2nd order triangulation stations which had different origins Consolidated into the Luzon Datum in 1911, however: No contiguous mean sea level datum established Disregarded geoid-ellipsoid separation Old geodetic data set had large errors - up to 56m in latitude & 80m in longitude Philippine Triangulation Network (1901 to 1911) From 1901 to 1911, the US Coast and Geodetic Survey established several small triangulation networks which had different origins. In 1911, these small networks were consolidated into the Luzon Datum and became the primary reference of all surveys in the Philippines. Analysis of the old data set reveals large errors (punching and typographical- up to 56m in lat and 80m in long). Old second order trig. Stations were recomputed and readjusted– thus giving a modified G.P. and a new name– Philippine Reference System 1992(PRS’92) There is a need for an accurate homogeneous national geodetic framework for improved economic status through better land management.

The Philippine Reference System of 1992 (PRS92) datum quantities are the same as Luzon 1911 datum except for the Geoid- Ellipsoid separation (N=0.34m). actually modified Luzon datum that has a more accurate and homogeneous set of coordinates A new network was established using GPS-- then called it the Geodetic Network of the Philippines Local coordinate system-LUZON DATUM 1911 All maps in Phil. were made using this datum This new network has a more accurate and homogeneous set of coordinates, referred to the Clark 1866 spheroid and the modified Luzon Datum which is named Philippine Reference System 1992. Semi-minor Axis Semi-major Axis Flattening (f) b a

Comparison Between PRS92 and GDA94 Datum Philippine Reference System Geocentric Datum of Australia Reference Ellipsoid Clarke 1866 GRS 1980 Semi-major axis 6,378,206.4 m 6,378,137.0 m Inverse flattening 294.978 298.257

The Philippine Reference System of 1992 (PRS92) NRMDP has established a new geodetic control network consisting of: 330 1st order 101 2nd order 36 3rd order

STANDARDS OF ACCURACY - (national geodetic network)  First Order : 10 Parts Per Million ( 10 PPM)  1 cm/Km 1/100,000  Second Order : 20 Parts Per Million ( 20 PPM)  2 cm/Km 1/50,000  Third Order : 50 Parts Per Million ( 50 PPM)  5 cm/Km 1/20,000  Fourth Order : 100 Parts Per Million ( 100 PPM)  10 cm/Km 1/10,000

PRS92 Transformation Parameters NRMPD also developed 7 parameter-transformation model relating PRS92 to WGS84 and vice-versa For GPS users, the following transformation parameters will be necessary when undertaking local surveys. They relate the WGS84 Datum, to which all GPS data is referenced to PRS92 on the Luzon Datum. These parameters are applied to WGS84 geocentric cartesian coordinates to give cartesian coordinates of the PRS92 datum which will then be transformed to geographical PRS92 coordinates.

Significance of PRS92 PRS 92 standardize the mapping system in the Philippines to ensure : Consistency of the country’s spatial datasets (topography, land use, boundaries, roads, environment, and natural resources, structures, etc) Efficient use of previously acquired data Availability of precise and accessible data for all users Improvement in the land administration and tenure system which forms the basis of all land transactions dealing with land Improvement in the surveying and mapping capabilities and support to vital government programs and projects Standardize the mapping system in the Philippines so that a particular point on the ground will have only one location in any official Philippine map. Provides the means through which base and thematic data sets can be consistently inter-related geographically

Triangulation Networks of the Philippines (1901 – 1911) THE NATIONAL GEODETIC FRAMEWORK Triangulation Networks of the Philippines (1901 – 1911) Densification (Horizontal) Homogeneous National Spatial Data Infrastructure LUZON DATUM (1911) Active Geodetic Network GND Leveling NRMDP (1989-92) Gravity Survey Tide Station PRS92 Program PRS92 Topo base map DTI Cadastral data ENR Data 330 -1st order 101 -2nd order 36 -3rd order National GNIS Regional

References: Galano, E. Why Surveyor Ignores the Earthcrust Drift. http://gepbohol.org/why%20surveying%20ignore.pdf Gatchalian, R. 2006, Manual on GPS Surveying, CGSD-NAMRIA Gatchalian, R. GPS Basics v 1.6 http://www.scribd.com/doc/28214647/GPS-Basics-v-1-6 Geoscience Australia 2011, http://www.ga .gov.au/earth-monitoring/geodesy/geodetic-datums/about.html PRS92 website http://www.namria.gov.ph/prs92/

Salamat

Relationship of Geoid and Ellipsoid Earth’s Surface Ellipsoid= h Geoid= H N = separation between ellipsoid and Geoid Determined by measurement or by modeling N N N N N h = H + N

Local Datum WGS84 Geoid Ellipsoid fitting North America & Philippines Ellipsoid fitting Europe WGS84 Geoid Local Datum: Ellipsoid that best fits the project area.

GPS Coordinate System GPS uses WGS 84 ellipsoid a= 6,378,137m; b=6,356,752.314m f= 1/298.25722 Geocentric Datum Cartesian coordinate system is the system used by GPS in defining the location of a point in space. It use distances in the X,Y and Z axes from the origin (center of ellipsoid)

The PRS92 Program Components Geodetic Network Development 18 The PRS92 Program Components Geodetic Network Development Transformation and Map Integration National and Regional Geodetic Network Information Systems Support Activities

Geodetic Network Development (GND) Continued the densification of the PRS92 network. 1st Order - 318 2nd Order - 723 3rd & 4th Order – 15,915

Data Transformation and Integration (DTI)

Data Transformation and Integration (DTI) DATA CONVERTION PREPARATION OF UNIFIED PROJECTION MAPS

National and Regional Geodetic Network Information Systems (GNIS)