GELE Cadastral Surveys & Land Laws — Cadastral and Isolated SurveysCheat Sheet
One-page cheat sheet for GELE Cadastral Surveys & Land Laws — Cadastral and Isolated Surveys. Every formula, definition, and key fact you need for this chapter, condensed to a single printable page. Designed for the final review session before the GELE 2026.
Exam context
The Geodetic Engineer Licensure Examination is conducted by Professional Regulation Commission (PRC) — Board of Geodetic Engineering and is scheduled for September 2026. The Cadastral Surveys & Land Laws subtest is marked as "Core" in the official pattern, and Cadastral and Isolated Surveys appears in position 1st of 5 in the GELE Cadastral Surveys & Land Laws review rotation. Passing mark: 70% weighted average, no sub-test below 50%. Recent GELE 2026 papers have drawn roughly a meaningful share of questions from this subject.
Cadastral and Isolated Surveys - Cheat Sheet
Your exam-ready quick reference for cadastral and isolated surveys, land monumentation, control ties, and Philippine land laws. Review the must-remember items and diagrams in the final 30 minutes before the PRC Geodetic Engineer Licensure Examination.
Sections
Section Title
Survey Types & Classification
Important Facts
- Cadastral = all parcels (systematic); isolated = one parcel (ad hoc).
- Cadastral surveys are DENR-LMB responsibility; isolated surveys may be private but must tie to cadastral control.
- Both types must reference PRS92 datum for absolute coordinates.
- Cadastral data feed the Torrens system (RA 496, Property Registration Decree of 1988).
- Parcel ID: lot number + cadastral block + cadastral case (e.g., Lot 5, Block 2, Cad-250).
Key Definitions
Term
Cadastral Survey
Example
Survey of all 500+ lots in a barangay for the cadastral map and Torrens registration.
Definition
Systematic survey of ALL parcels within a municipality or city to fix and record boundaries for land registration, conducted by DENR-LMB.
Term
Isolated (Individual) Survey
Example
Resurveying one titled lot to verify boundary for a fence installation.
Definition
Survey of a SINGLE lot for titling, transfer, relocation, or development; tied to existing cadastral/geodetic control.
Term
Relocation Survey
Example
Finding and monumenting corners of a lot whose original markers have been destroyed.
Definition
Isolated survey to re-establish boundary marks of a parcel using original technical description and cadastral references.
Term
Public-Land Survey
Example
Surveying a timber concession area or homestead application.
Definition
Survey of alienable public lands for homestead, timber, or mineral purposes; approved by DENR.
Diagrams To Know
- Cadastral block layout (showing lot numbers and block arrangement).
- Isolated survey sketch (single lot with tie line to nearest control monument).
- Hierarchical relationship: municipality → cadastral case → cadastral block → lot.
Common Values
Value
0.20 m × 0.20 m × 0.60 m (h)
Symbol
Std. BL marker
Quantity
Standard concrete monument dimensions
Value
40–50 m
Symbol
Urban intervals
Quantity
Typical monument spacing (urban)
Value
100+ m
Symbol
Rural intervals
Quantity
Typical monument spacing (rural)
Value
6,378,137 m
Symbol
a (WGS84)
Quantity
PRS92 ellipsoid semi-major axis
Value
1/298.257223563
Symbol
f (WGS84)
Quantity
PRS92 ellipsoid flattening
Section Title
Monumentation & Control Ties
Important Facts
- Every parcel corner must be tied to a BLLM or geodetic control point — no isolated geometry.
- Tie = distance (m) and bearing (degrees, minutes, seconds) from corner to control monument.
- Monumentation materials: concrete, stone, or iron (stainless steel caps recommended in saltwater zones).
- Monument intervals typically 40–50 m in urban areas, wider in rural zones.
- BLLMs are usually at municipal halls, schools, or public buildings for accessibility.
- Bearing is measured from north of the meridian (true, magnetic, or grid); use PRS92 grid north in PPCS.
- Coordinate system: PRS92 (WGS84 ellipsoid) with PPCS (UTM variant) projection.
- Tie survey must precede parcel corner survey to establish absolute position.
Key Definitions
Term
Monument (Marker)
Example
Reinforced concrete pillar (0.20 m × 0.20 m × 0.60 m) with brass cap and parcel/block number.
Definition
Permanent, durable boundary mark installed at parcel corners; concrete, stone, or official BL/BLLM markers.
Term
BLLM (Bureau of Lands Location Monument)
Example
Concrete monument at a municipal center or known landmark, coordinates surveyed to PRS92.
Definition
Official geodetic control monument established and maintained by DENR-LMB; provides absolute reference for parcel ties.
Term
Tie Line (Control Tie)
Example
Corner A of Lot 5 is 127.45 m on bearing 045°15'30" from BLLM-250-A.
Definition
Distance and bearing from a parcel corner to the nearest BLLM or geodetic control point; gives parcel absolute coordinates.
Term
Geodetic Control
Example
Third-order or fourth-order control points established by NAMRIA or DENR-LMB.
Definition
Network of survey-grade monuments with precisely determined coordinates on PRS92; provides datum for all cadastral surveys.
Diagrams To Know
- Monument cross-section (showing depth, cap, and reference mark).
- Tie-line diagram (parcel corner to BLLM with distance and bearing).
- Coordinate system diagram (true north, grid north, magnetic north).
Common Values
Value
1:500 to 1:1000
Symbol
Urban scale
Quantity
Cadastral map scale (urban)
Value
1:1000 to 1:2000
Symbol
Rural scale
Quantity
Cadastral map scale (rural)
Value
0.01 m (1 cm)
Symbol
Cadastral precision
Quantity
Minimum distance precision
Value
DMS (±1 sec) or dec. deg. (±0.0001°)
Symbol
Bearing precision
Quantity
Bearing notation precision
Section Title
Cadastral Survey Process & Documentation
Important Facts
- Cadastral map scale: typically 1:500 (urban) to 1:2000 (rural) depending on lot density.
- Bearing origin: grid north (PPCS/UTM) referenced to PRS92 datum.
- Distance units: meters (m), to 0.01 m precision minimum.
- Bearing precision: degrees, minutes, seconds (DMS) or decimal degrees.
- Monument positions plotted on cadastral map to ±0.1 m accuracy.
- Lot data (area, corner coords, technical description) recorded in cadastral register.
- Cadastral map filed at DENR-LMB and municipal assessor's office.
- Approved cadastral map is basis for Torrens land registration.
- Field survey must be tied to at least two independent BLLMs for validation.
Key Definitions
Term
Cadastral Map
Example
1:500 to 1:1000 scale map with 200+ lots, block lines, and azimuths marked.
Definition
Large-scale map showing all parcels in a municipality with lot numbers, block numbers, boundaries, and monument locations.
Term
Technical Description
Example
"From corner A, N 45°30'00" E, 125.50 m to corner B; thence S 44°20'15" E, 98.75 m to corner C..." etc.
Definition
Textual description of a parcel's boundaries by bearings and distances, starting from a known point.
Term
Lot Number
Example
Lot 27 in Block 5 of Cad-Case 250-Brgy. Pag-asa.
Definition
Unique identifier for a parcel within a cadastral block; assigned sequentially by DENR-LMB.
Term
Cadastral Block
Example
Block 3 contains Lots 1–15, all fronting on Magsaysay Avenue and San Pablo Street.
Definition
Group of parcels bounded by streets or roads; all lots within a block share a block number.
Term
Cadastral Case
Example
Cad-Case 250 = entire cadastral survey of Nueva Ecija municipality.
Definition
Complete cadastral survey project for a municipality or city; all blocks and lots fall within one case number.
Diagrams To Know
- Sample cadastral map section (4–6 blocks with lot numbers and street names).
- Bearing and distance annotation on a parcel (e.g., N 45°30'00" E, 125.50 m).
- Monument reference mark (showing elevation, cap type, and coordinates).
Section Title
Philippine Agencies & Legal Framework
Important Facts
- RA 4374 (Cadastral Act of 1965): primary law authorizing cadastral surveys in the Philippines.
- RA 8560 (Agriculture and Fisheries Modernization Act): amends RA 4374, accelerates cadastral survey.
- PD 1529 (Property Registration Decree of 1988): Torrens system for land registration; cadastral data feed into PD 1529.
- CA 141 (Public Land Act): governs public-land disposal and classification; cadastral surveys identify public vs. private land.
- Geodetic Engineer must be licensed (PRC) and must supervise all cadastral/isolated surveys in the Philippines.
- DENR-LMB approval required before any cadastral survey fieldwork begins.
- Cadastral survey results filed at LMB regional office and municipal assessor.
- Torrens title (from cadastral data) is indefeasible after one-year period (PD 1529).
- Geodetic datum: PRS92 (Philippine Reference System 1992) = WGS84 with local adjustments.
- Projection: PPCS (Philippine Position Classification System) = UTM variant with false easting/northing.
Key Definitions
Term
DENR (Department of Environment and Natural Resources)
Example
Issues land titles, approves cadastral surveys, maintains land records.
Definition
Philippine government agency responsible for land management, cadastral surveys, and public-land administration.
Term
LMB (Land Management Bureau)
Example
Calauan LMB Office approves all cadastral surveys in Laguna.
Definition
Sub-agency of DENR overseeing cadastral surveys, land titling, and boundary disputes; regional offices in each province.
Term
BLGS (Bureau of Lands Geodetic Survey)
Example
Historical reference in older documents; modern equivalent is DENR-LMB.
Definition
Superseded unit; cadastral survey authority now housed within LMB.
Term
NAMRIA (National Mapping and Resource Information Authority)
Example
Establishes and maintains third-order control points; publishes official datum parameters.
Definition
Government agency maintaining geodetic control network and producing topographic/orthophoto maps on PRS92.
Diagrams To Know
- Organizational flow chart (DENR → LMB → Regional Office → Municipal Assessor).
- Land registration workflow (cadastral survey → LMB approval → Torrens registration → title issuance).
- Geodetic datum hierarchy (WGS84 ellipsoid → PRS92 local datum → PPCS projection).
Formulas
Formula
Parcel Area = (1/2) × |Σ(x_i × y_{i+1} − x_{i+1} × y_i)|
Meaning
Shoelace formula for polygon area from Cartesian coordinates; x_i, y_i are corner coordinates in order.
Watch Out
Coordinates must be in order (clockwise or counterclockwise); missing or mis-ordered corners give wrong area or negative result.
When To Use
Computing area of a surveyed parcel from corner coordinates; closes the polygon.
Formula
Bearing_Grid = Bearing_Magnetic + Magnetic_Declination
Meaning
Bearing_Grid = grid bearing; Bearing_Magnetic = compass bearing; Magnetic_Declination = angular difference (east or west).
Watch Out
Declination changes with location and year; use current declination from NAMRIA; add east decl., subtract west decl.
When To Use
Converting compass (magnetic) bearings to grid bearings for PRS92/PPCS surveys.
Formula
Distance_Grid = Distance_Ground × (cos(elevation_angle)) / Scale_Factor
Meaning
Distance_Grid = horizontal distance on grid; Distance_Ground = measured slope distance; cos(elevation_angle) = horizontal component; Scale_Factor = PPCS UTM factor (~0.99962).
Watch Out
Slope distance reduction is critical; neglecting elevation correction introduces 0.1–1 % errors in parcel boundaries.
When To Use
Reducing measured slope distance to grid distance for cadastral records.
Section Title
Isolated Survey Details & Procedures
Important Facts
- Isolated survey must start with control tie before any lot boundary measurement.
- Corner coordinates are computed from tie coordinates + offset vectors (bearing and distance).
- At least two independent corners must be tied to two BLLMs (cross-tie) for validation.
- Monument type and position must match cadastral map symbols and description.
- Isolated survey sketch must show: parcel outline, corner numbers, bearings, distances, tie line(s), and adjacent lot reference.
- Technical description in isolated survey follows cadastral standard: start point, bearing-distance chain around parcel.
- Parcel area computed from corner coordinates (Shoelace formula); compared with cadastral record for closure check.
- Field notes must record: monument condition, tie measurements, corner coordinates, sketch.
- Survey permit (or exemption) from LMB required; licensed geodetic engineer must sign.
- Isolated survey data are filed at LMB and municipal assessor for land registration.
Key Definitions
Term
Relocation Survey
Example
Owner of Lot 8, Block 3, Cad-250 commissions resurvey to replace destroyed corner monuments.
Definition
Isolated survey to re-establish lot boundary using original technical description and cadastral control.
Term
Verification Survey
Example
Buyer hires surveyor to verify boundary before purchase; no new monuments installed.
Definition
Isolated survey to confirm existing lot boundaries without monumentation changes; used for title transfer or dispute prevention.
Term
Subdivision Survey
Example
Lot 12 (5,000 m²) subdivided into Lot 12-A (3,000 m²) and Lot 12-B (2,000 m²).
Definition
Isolated survey dividing one lot into two or more sub-parcels; each sub-parcel gets new lot number and technical description.
Term
Control Tie (Cadastral Tie)
Example
Corner A of Lot 5 is 142.30 m on bearing 062°45'15" from BLLM-250-D.
Definition
Measurement from parcel corner to nearest BLLM or third-order control point; provides absolute position.
Diagrams To Know
- Isolated survey sketch (single lot with control tie, corner numbers, bearings, distances).
- Subdivision diagram (original lot and sub-lot boundaries with new lot numbers).
- Corner coordinate computation from tie (starting BLLM coords + tie offset + parcel offsets).
Formulas
Formula
UTM_Easting = 500,000 + ρ × sin(θ)
Meaning
UTM_Easting = easting coordinate (m); ρ = distance from central meridian (m); θ = bearing from north; 500,000 = false easting.
Watch Out
False easting (500 km) prevents negative coordinates; do NOT forget it; PPCS uses identical structure.
When To Use
Converting polar (bearing, distance) to Cartesian (E, N) in PPCS/UTM.
Formula
UTM_Northing = ρ × cos(θ) + k0 × M
Meaning
UTM_Northing = northing coord. (m); k0 = scale factor (~0.99962); M = arc distance from equator (m).
Watch Out
Scale factor k0 compresses distances near meridian; ignore at your peril for long-distance cadastral ties.
When To Use
Computing UTM northing (grid north distance) for PRS92 geodetic position.
Common Values
Value
120°E
Symbol
CMZ1
Quantity
PPCS central meridian (Luzon Zone 1)
Value
121°30'E
Symbol
CMZ2
Quantity
PPCS central meridian (Luzon Zone 2)
Value
123°E
Symbol
CMZ3
Quantity
PPCS central meridian (Luzon Zone 3)
Value
0.99962
Symbol
k0 (UTM)
Quantity
PPCS scale factor (k0)
Value
500,000 m
Symbol
E0
Quantity
False Easting (PPCS/UTM)
Value
0 m (or 10,000,000 m in southern hemisphere)
Symbol
N0
Quantity
False Northing (PPCS/UTM)
Section Title
Coordinate Systems & Datums for Cadastral Surveys
Important Facts
- PRS92 uses WGS84 ellipsoid: a = 6,378,137 m, f = 1/298.257223563.
- PPCS divides Philippines into 4 zones (Luzon Zones 1–3, Mindanao Zones 1–2); each has central meridian.
- UTM scale factor k0 = 0.99962 near central meridian; distance contracts by 0.038 % at zone edge.
- For cadastral ties < 500 m, scale factor correction is negligible (< 2 mm); for longer ties, must apply.
- Bearing origin = grid north (PPCS); use compass bearings with declination correction.
- Conversions: GPS (WGS84) → PRS92 (negligible for Philippines) → PPCS grid coordinates.
- Cadastral map printed in PPCS grid; grid lines shown at 1 km or 500 m intervals.
- Zone boundary: surveys crossing zones must have coordinates in both zones or use transverse tie.
- NAMRIA publishes PRS92 ellipsoid parameters, PPCS formulae, and annual magnetic declination for each province.
Key Definitions
Term
PRS92 (Philippine Reference System 1992)
Example
All DENR cadastral surveys use PRS92 coordinates; equivalent to WGS84 for practical purposes.
Definition
Geodetic datum for the Philippines; based on WGS84 ellipsoid with local adjustments; official reference for all surveys.
Term
WGS84 (World Geodetic System 1984)
Example
GPS receivers output WGS84 by default; converted to PRS92 for Philippine official use.
Definition
Global ellipsoid and geodetic datum; PRS92 is a localized realization of WGS84 for the Philippines.
Term
PPCS (Philippine Position Classification System)
Example
Luzon Zone 3 covers east of 122°E; coordinates are 6-digit eastings and 7-digit northings in meters.
Definition
Conformal map projection (UTM variant) using PRS92 datum; divided into zones for the Philippines.
Term
False Easting / False Northing
Example
A point 10 km west of central meridian has easting 490,000 m (not −10,000 m).
Definition
Artificial offset added to zone origin to ensure all coordinates are positive; 500,000 m easting, 0 m northing (UTM standard).
Term
Grid North vs. Magnetic North vs. True North
Example
In Metro Manila, grid north ≈ true north (small convergence); magnetic declination ≈ +4° east of true north.
Definition
Grid north = PPCS projection north; True north = geographic pole; Magnetic north = compass heading.
Diagrams To Know
- PPCS zone map (showing 4 zones for Philippines with central meridians).
- UTM grid overlay on cadastral map (showing grid north lines and false easting/northing origin).
- Bearing diagram (true north, grid north, magnetic north with convergence angle).
Section Title
Common Pitfalls & Exam Traps
Important Facts
- TRAP: Confusing cadastral (all parcels, systematic) with isolated (one parcel) — they are opposite in scope.
- TRAP: Forgetting tie line — every parcel corner MUST be tied to BLLM; isolated geometry alone is invalid.
- TRAP: Using magnetic bearing without declination correction — causes ~2–4° error in boundaries.
- TRAP: Ignoring scale factor — 0.05 m error over 500 m tie if k0 omitted.
- TRAP: Mixing WGS84 with PRS92 — PRS92 is mandatory in Philippines; WGS84 is global reference.
- TRAP: Monument spacing confusion — urban 40–50 m, rural 100+ m; exam may ask which is correct for area type.
- TRAP: Parcel identification — lot number alone is insufficient; must include block number and cadastral case.
- TRAP: Confusing BLLM with BLGS — BLLM = monument; BLGS = old unit (now LMB).
- TRAP: Agency responsibility — cadastral approval is DENR-LMB, not DPWH or BIR.
- TRAP: Bearing notation — always use DMS (D°M'S") or decimal degrees; never mix or omit units.
Must Remember
- 1. CADASTRAL = all parcels (systematic survey by DENR-LMB); ISOLATED = one parcel (private surveyor, tied to cadastral control).
- 2. Every parcel corner MUST be tied to a BLLM or geodetic control point with bearing and distance; isolated geometry is invalid.
- 3. Parcel identification: Lot # + Block # + Cadastral Case (e.g., Lot 5, Block 2, Cad-250); this triplet is unique.
- 4. DENR-LMB (not DPWH, not BIR) approves all cadastral and isolated surveys; regional offices issue permits.
- 5. PRS92 datum (based on WGS84) and PPCS/UTM projection are mandatory for all Philippine cadastral surveys.
- 6. Monument types: BL marker (parcel corners), BLLM (control tie point); concrete, brass cap, at least 0.20 × 0.20 × 0.60 m.
- 7. Monument spacing: urban 40–50 m, rural 100+ m; smaller intervals = better control density.
- 8. Bearing origin = grid north (PPCS); convert compass (magnetic) bearings using current declination (~±4° in Philippines).
- 9. Scale factor k0 = 0.99962 (PPCS/UTM); apply to distances > 500 m for accuracy; neglect causes ~0.05 m error per km.
- 10. Cadastral map output: large-scale (1:500–1:2000), lot numbers, block lines, monument positions, filed at LMB + municipal assessor; basis for Torrens titles.
Last Minute Tips
- TIP 1 — On exam, if asked 'What is a cadastral survey?', answer IMMEDIATELY: 'Systematic survey of ALL parcels in a municipality, conducted by DENR-LMB, tied to BLLM control, output is cadastral map + Torrens registration.' This is THE definition; any other answer is wrong.
- TIP 2 — If asked about a tie line, ALWAYS include THREE components: (1) starting control monument (BLLM name/number), (2) distance in meters (to 0.01 m), (3) bearing in DMS or decimal degrees. Example: 'BLLM-250-A, 142.30 m, bearing 062°45'15".' Missing any one = no points.
- TIP 3 — When comparing cadastral vs. isolated surveys, use this mental checklist: Cadastral = DENR does it, all lots, big map; Isolated = surveyor does it, one lot, sketch. Reverse any of these? WRONG.
- TIP 4 — Monument question? Concrete + brass cap + 0.20 × 0.20 × 0.60 m = standard BL marker. BLLM is larger, more official, has coordinates engraved. Do NOT say 'BLLM is just a BL marker'—exam will mark wrong.
- TIP 5 — For any bearing/distance problem, ALWAYS convert to grid bearing (apply declination if starting with magnetic) and reduce slope distance (apply k0 scale factor if > 500 m). Show your steps; partial credit often awarded for method even if final answer slightly off.
Comparison Tables
Rows
Values
- ALL parcels in municipality/city
- ONE parcel only
Property
Scope
Values
- Systematic land registration & taxation
- Titling, transfer, relocation, or subdivision
Property
Purpose
Values
- DENR-LMB (government)
- Private surveyor (licensed geodetic engineer)
Property
Conducting Agency
Values
- DENR-LMB regional office & municipal assessor
- DENR-LMB (may be exempt for relocation)
Property
Approval
Values
- Cadastral map (large-scale) + lot data register
- Survey sketch, technical description, coordinates
Property
Output
Values
- All blocks/lots tied to BLLM network
- Single lot tied to 1–2 nearest BLLMs
Property
Tie Requirement
Values
- Months to years (large municipality)
- Days to weeks (single lot)
Property
Duration
Values
- High (government/donor-funded)
- Moderate (private contract)
Property
Cost
Values
- PRS92 + PPCS/UTM
- PRS92 + PPCS/UTM (aligned with cadastral)
Property
Datum/Projection
Values
- 50–500+ per cadastral case
- 1 (single lot)
Property
Typical Lot Numbers
Columns
- Aspect
- Cadastral Survey
- Isolated Survey
Table Title
Cadastral Survey vs. Isolated Survey
Rows
Values
- Reinforced concrete
- 0.20 m × 0.20 m × 0.60 m (h)
- Brass or stainless steel cap with center mark
- Parcel corners, cadastral survey
Property
BL (Bureau of Lands) Marker
Values
- Reinforced concrete (buried stone allowed)
- Larger, 0.30 m × 0.30 m × 1.0 m (h) or more
- Brass cap with reference mark & coordinates
- Geodetic control tie point, long-term reference
Property
BLLM (Bureau of Lands Location Monument)
Values
- Iron or steel pipe (1–2 inch dia.)
- 0.60–1.0 m length, driven 0.30–0.50 m deep
- Paint mark or nail/punch on top
- Temporary boundary, construction/relocation survey
Property
Iron Pipe/Stake
Values
- Natural stone (rocks stacked)
- Height 0.30–0.60 m
- Painted cross or chiseled X
- Rural/remote areas where concrete impractical
Property
Stone Cairn
Values
- Reinforced concrete, often buried
- Large, 0.50+ m cube or more
- Brass cap or underground mark
- NAMRIA control points for geodetic network
Property
Third-Order Control Pillar
Columns
- Monument Type
- Material
- Dimensions (typical)
- Cap/Mark
- Use Case
Table Title
Monument Types & Standards
Rows
Values
- 1965
- Authorizes systematic cadastral surveys in Philippines
- PRIMARY law enabling all cadastral projects; DENR-LMB mandate
Property
RA 4374 (Cadastral Act)
Values
- 1978
- Torrens system for land registration (indefeasible titles)
- Cadastral data feed into Torrens registration; 1-year confirmation period
Property
PD 1529 (Property Registration Decree)
Values
- 1936 (codified)
- Governs public-land classification, alienation, and homesteading
- Cadastral survey identifies public vs. private; homestead applications require survey
Property
CA 141 (Public Land Act)
Values
- 1998
- Accelerates cadastral survey for agricultural lands
- Expanded DENR-LMB authority; faster survey and titling for farm parcels
Property
RA 8560 (AFMA Amendment to RA 4374)
Values
- Various
- All land in Philippines is state property unless titled
- Underlies cadastral system: survey confirms ownership via Torrens title
Property
RA 10027 (Regalian Doctrine, historical)
Columns
- Law / Decree
- Year
- Key Authority / Purpose
- Relevance to Cadastral Surveys
Table Title
Philippine Legal Framework for Land Surveys
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