Survey Symbols and Geodetic Control Procedures

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Questions and Answers

What should be the distance within which 2nd and 3rd Order geodetic control stations are absent from the project boundary?

20km

15km

5km

10km (correct)

Which survey symbol is used for a Free Patent Application?

F (correct)

Which type of geodetic control points should be used in the design of a Control Network?

Only recently established points

Only stable or undisturbed points (correct)

Only points from recent surveys

Any points within the project area

What does the symbol 'Tsa' represent in public land surveys?

Townsite Sales Application Signup and view all the answers

What is the maximum distance between 1st order control points in a Primary Geodetic Network?

50 km Signup and view all the answers

Which of the following survey symbols signifies a Lease Application for an Agricultural Individual?

Li Signup and view all the answers

What does the abbreviation 'Gss' stand for in the context of survey symbols?

Group Settlement Surveys Signup and view all the answers

Which of the following is NOT required to be notified in writing before conducting a survey?

Local school principal Signup and view all the answers

What is a characteristic of the network design for GNSS observations?

Specific terrain and physiographic features must be considered Signup and view all the answers

Which symbol represents an Agricultural Colony in public land surveys?

Ac Signup and view all the answers

In designing a network of controls, how many GNSS receivers are considered sufficient?

More than three Signup and view all the answers

The symbol 'Mli' in land surveys refers to which type of application?

Lease Application (Agricultural): Individual Signup and view all the answers

What is the purpose of using closed polygons in network design?

To create a rigid network Signup and view all the answers

Which survey symbol corresponds to a Miscellaneous Sales Application by Charitable Institution and Corporation?

Msc Signup and view all the answers

Which order of control points should have a maximum distance of 2 km between pairs?

4th Order Signup and view all the answers

Which factor is NOT relevant for network design considerations?

Recent weather patterns Signup and view all the answers

What is the minimum number of known PRS 92 control points required in the designed Network?

Three Signup and view all the answers

Why should field observations be timed when the Position Dilution of Precision (PDOP) is low?

It suggests a higher probability of accuracy. Signup and view all the answers

Which factor is NOT considered during the reconnaissance process when determining control points?

Proximity of public transportation Signup and view all the answers

What are the latitude coordinates of Balanacan station?

13° 33‘ 41.000“ N Signup and view all the answers

What feature describes the station mark at Balanacan?

A round hole 1.5 cm in diameter Signup and view all the answers

What is the primary purpose of conducting reconnaissance in the area?

To determine if control points need to be transferred to strengthen weak geometric figures. Signup and view all the answers

Who established the Balanacan station?

Mr. O.W. Ferguson and Mr. H.D. King Signup and view all the answers

Which of the following dimensions corresponds to the First Order Accuracy control monument?

120 cm above ground Signup and view all the answers

What aspect of the travel time estimation is necessary for the survey team during reconnaissance?

Travel time from the field office to the project site Signup and view all the answers

What is the depth of the hole at the station mark in Balanacan?

6 cm Signup and view all the answers

How is a geodetic station defined to be in the Luzon Datum?

If it has connections by continuous triangulation from Balanacan Signup and view all the answers

Which of the following best describes the standard dimensions for a Third Order Accuracy control monument?

25 x 25 cm top, 35 x 35 cm bottom Signup and view all the answers

What type of obstructions are surveyed during reconnaissance that may disrupt data transmission?

Radio station towers Signup and view all the answers

What was the purpose of the Philippine Geodetic Network (PGN)?

To conduct topographic and hydrographic surveys Signup and view all the answers

What type of triangulation was predominantly used in the PGN?

2nd order triangulation Signup and view all the answers

Where were the triangulation stations of the PGN mainly concentrated?

Along the coastal areas Signup and view all the answers

What does a low GDOP value indicate during a GNSS session?

Better satellite geometry for accurate positioning Signup and view all the answers

What minimum number of observations is required to achieve 1st Order accuracy?

3 observations Signup and view all the answers

Which of the following actions should be avoided within 10 meters of a GPS receiver?

Using a radio Signup and view all the answers

What is the recommended number of observations for achieving 2nd Order accuracy?

3 or more observations Signup and view all the answers

What is a potential consequence of not downloading stored data from the receiver promptly?

Loss of previous data due to memory overload Signup and view all the answers

What does PDOP stand for?

Position Dilution of Precision Signup and view all the answers

How long does it take to retrieve data from a satellite when 6 or more satellites are used?

10 minutes Signup and view all the answers

What is the effect of using older Geodetic Control Points in network design?

They can be observed alongside new control points Signup and view all the answers

Study Notes

Project Control Accuracy Specifications & Survey Symbols

In the absence of 2nd and 3rd order geodetic control stations within 10km of the project boundary, connect to an LMB-certified reference point.
Survey symbols (DMC 2010-13 Annex I) define land use types (e.g., Reclaimed Land Lease Application (Rlla), Agricultural Colony (Ac), Lease Applications, etc.). Refer to the provided text for a complete list.
Balanacan Station (Luzon Datum of 1911): Latitude 13° 33‘ 41.000“ N, Longitude 121° 52‘ 03.000“ E. Marker is a hole (1.5cm diameter, 6cm deep) in a triangle (16cm sides) in hard rock.
Luzon Datum 1911 stations established by O.W. Ferguson and H.D. King; connected by continuous triangulation from Balanacan Station. The Philippine Geodetic Network (PGN), developed until 1946, comprised coastal 2nd order triangulation stations. Only stable control points are usable.
Before surveying, notify: Provincial Engineer, PENRO, DPWH District Engineer, CENRO, Municipal Engineer, Head of Field Office, Barangay Chairman, and Lot owner/claimant.
Surveys begin and end at established PRS 92 control points for checks. Baseline lengths for different orders of accuracy are specified (e.g., 1st order - 50km; 2nd order - 25km; 3rd order - 5km; 4th order - variable, but each barangay needs at least one pair within 2km).

Network Design & Reconnaissance

Inter-visibility isn't crucial for GNSS; select stable, accessible points unaffected by future construction; avoid swampy areas.
Network design considers terrain, available geodetic controls, number of GNSS receivers (3+ sufficient), and observation length/type. See Section 25 for details.
The network should form closed polygons (triangles preferred) with at least three known PRS 92 control points for each station; include redundancy. Conduct observations with low PDOP (Position Dilution of Precision) for better accuracy.
Reconnaissance determines accessibility, ground stability, routes, radio tower proximity (obstructions above 15°), travel time between stations, number/status of old control points, and required property permissions.

Geodetic Control Monuments & Connections

Monument dimensions vary by accuracy order (First-Fourth Order). Specifications are given for top and bottom cross-section sizes and lengths above/below ground. Sizes are given in centimeters.
Minimum and recommended observation numbers for connecting to existing controls of the same or higher order are: 1st order (3 min, 4+ rec), 2nd order (2 min, 3+ rec), 3rd order (2 min, 2 rec).

Observations & Old Control Points

During GNSS sessions, monitor GDOP (Geometric Dilution of Precision); lower GDOP is better. Download data promptly, manage receiver memory to avoid overloads, and avoid electronic devices within 10 meters of the receiver.
Include old geodetic control points in the network design (Sections 6, 11, and 12).

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Description

This quiz covers the specifications for project control accuracy and the associated survey symbols used in land use classification. It includes information about connecting to reference points, geodetic control stations, and proper notification procedures before surveying. Test your knowledge on these essential surveying concepts.