PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
June 2017
395
This series of new observations was adjusted and published
as the Philippine Reference System of 1992 (PRS92). Accord-
ing to NAMRIA this included the establishment of an EDM
calibration baseline, and the determination of the seven Bur-
sa-Wolf transformation parameters between the Luzon Datum
of 1911 and WGS 84. Those parameters fromWGS84 to PRS92
are published as: ΔX = +127.623 meters, ΔY = +67.245 meters,
ΔZ = +47.043 meters, Scale = +1.06002 X 10
-6
, R
x
= +3.07”,
R
y
= –4.90”, and R
z
= –1.58”. No accuracy statements were
published with the parameters. Since this work was done with
Australian government assistance, the sign of the rotation pa-
rameters is assumed to be the standard right-handed system
favored in Australian and U.S. practice. Although some may
favor the designator “PRS92,” it is in fact still the original Lu-
zon Datum of 1911 with published transformation parameters
from WGS84 Datum. The original Datum observations were
not recomputed. It is hoped that NAMRIA will resume their
collaboration with the U.S. National Imagery and Mapping
Agency and seek consulting services to modernize their geo-
detic system. An individualized geoid model would be a wel-
come foundation to this hypothetical datum.
U
pdate
“NAMRIA is spearheading the establishment of the Philippine
Active Geodetic Network (AGN) as part of the implementation
of the PRS92 Project. As envisioned, the AGN will be composed
of stations strategically located all over the country which
continuously provide geographic data. To date, all six Active
Geodetic Stations (AGS) have already been set up: four are
roof-based (NAMRIA Main Building in Taguig, Urdaneta City
Hall in Pangasinan, Registry of Deeds Building in Tagaytay,
and Basa Air Base in Floridablanca, Pampanga) while two
are ground-based (Nueva Ecija University of Science and
Technology in Cabanatuan City and 415th Police Provincial
Mobile Group in Candelaria, Quezon). All six are ready for
interconnectionto thenetwork. For theDataandControlCenter
(DCC), the installation of the Center’s ICT requirements has
been completed. Support systems needed in the operation and
maintenance of the DCC, such as fire suppression and access
control systems, have already been configured and tested. The
Horizontal Control Network established 2,367 second-order
and third-order GCPs, and established 5,286 fourth-order
GCPs. For the Vertical Control Network, 17,410 km of level
lines were surveyed. About 65 first-order GCPs were recovered
and observed from 2009 until June 2010. Processing and
adjustments of GCPs using the Active Geodetic Station (AGS)
– PageNET in Taguig City as reference control were finished in
July 2010. These zero-order points are now available for use as
reference points in geodynamic studies. Around 362 first-order
GCPs have been contracted out in six clusters for recovery and
re-observation. This activity will update the coordinates of
the first-order GCPs established under the Natural Resources
Management Development Project (NRMDP) in 1989. Some
300 GCPs were recovered and observed by contractors and
GPS data are being evaluated. Nine clusters of benchmarks in
loops were recovered and observed using the Global Positioning
System to determine the relationships of the Mean Sea Levels
(MSL) of the major islands in the Philippines to the National
Vertical Datum. As of May 2011, all of the nine clusters of
benchmarks in loops were observed, processed and MSL
relationships observed. Some
80 first-order gravity stations
will be established nationwide for scientific applications and
for the formulation of a Philippine geoid model. As of May
2011, established are 80 first-order and 68 second-order
gravity stations. Around 5,000 kilometers of level line will be
surveyed to connect the GCPs to the existing benchmarks to
compute the Geoid undulations. The activity is essential in
the computation of the Geoid model of the Philippines. The
project is ongoing. The NAMRIA PRS92 Data Integration
Task Group continued to under take the quality control
of cadastral datasets for Ilocos province-Region I and the
National Capital Region (NCR). All plotted lots are currently
being converted from local to grid coordinates. In compliance
with the agreements reached during the PRS92 Coordinating
Conference held on 18 April 2011, the Task Group conducted
a retraining program and lecture on the derivation of local
transformation parameters of Regions III, VII, VIII, IX, and
XIII. This is also in pursuance of the commitment of NAMRIA
to Provide relevant technical assistance and support for the
full adoption of PRS92 and enhancement on the capability of
the regional offices. On the other hand, the surveying arm of
the Task Group is presently establishing image control points
(ICPs) at the northern portion of Bohol province. Said ICPs
will be used for the transformation of satellite imageries into
PRS92. A total of 48 ICPs for four map sheets covering the
Province of Bohol is set to be established. Similarly, a total of
70 photo control points (PCPs) were established in the Province
of Aklan. Additional 12 PCPs were established in Casiguran,
Aurora. At present, the processing of Global Positioning
Systems (GPS) raw data and of PCP Description Sheets was
finished and they are ready for submission. A total of 161
PCPs covering Casiguran, Eastern Laguna de Bay, North
Western Panay, and Pampanga is set to be established for use
in the large scale topographic base mapping under the PRS92
project. There are three developed systems currently installed
in 18 regions of the country. These are the regional Geodetic
Network Information System (GNIS), the Land Survey Data
Management System (LSDMS), and the Metadata Entry for
environment and natural resources datasets. As of May 2011,
Regions 1,2,5,7,8,11, and CAR were visited for the update of
regional GNIS and LSDMS, and installation of the 4-parameter
derivation program and online synchronization module of both
systems.”
(NAMRIA, 22 March 2017).
The contents of this column reflect the views of the author, who is
responsible for the facts and accuracy of the data presented herein.
The contents do not necessarily reflect the official views or policies of
the American Society for Photogrammetry and Remote Sensing and/
or the Louisiana State University Center for GeoInformatics (C
4
G).
This column was previously published in
PE&RS
.
