Question & AnswerQ&A (DENR MEMORANDUM CIRCULAR NO. 2010-06)
The circular provides standards and procedures for converting and transforming cadastral data and surveys into the Philippine Reference System of 1992 (PRS92) to ensure spatial consistency, data integration, quality, and accessibility.
The manual covers the transformation and integration of all cadastral data into PRS92 and outlines database management mechanisms for the transformed data.
Cadastral data refers to records of cadastral and isolated surveys detailing land parcels based on their boundaries.
They are numerical constants used to transform local or area-based coordinates into the PRS92 coordinate system.
In their absence, lot description sheets are used. If these are also unavailable, reconstruction is done from original field notes. If none of these are retrievable, a resurvey under PRS92 is conducted.
Only persons authorized under RA 8560, as amended by RA 9200 (The Geodetic Engineering Act), knowledgeable in GNSS surveys, can conduct these surveys.
Unauthorized copying or transfer is subject to penalties under applicable laws, rules, and regulations as stated in Section 10.
It is a linear conformal transformation involving rotation, scaling, and translation described by equations involving parameters A, B, C_E, and C_N applied to old coordinate values to obtain PRS92 coordinates.
Regional offices implement quality control measures to ensure data integrity. Discrepancies in untitled/undecreed parcels are rectified by LMS regional offices, while titled parcels require court proceedings for corrections.
LMB oversees the survey and cadastral data transformation, manages the cadastral database, provides conversion guidelines, and collaborates with NAMRIA in assessing transformation accuracy.
It is a digital collection of cadastral data including coordinates, bearings, distances, descriptions, sketches, and converted cadastral maps organized for easy access and retrieval.
Composite Survey Teams undertake reconnaissance and recovery of control points, conduct GPS or conventional surveys for PRS92 coordinates, prepare reports with monument recovery sheets, and submit them for evaluation and approval.
CSDA serves as the framework for organizing cadastral survey metadata and data to facilitate efficient access, management, and use of cadastral information in PRS92.
LMS regional offices may outsource data conversion and survey if their staff cannot manage the workload, provided the cost does not exceed prevailing unit costs and follows existing rules and regulations.
Steps include encoding recovered point coordinates, computing transformation parameters via four-parameter transformation, analyzing residual errors, validating accuracy using check points and adjoining project verifications, and obtaining official approval.