- Other Acceptable Lot Corner Markers
By LPH LSS
In our previous article, we introduced the standard marker used by Geodetic Engineers (GE) in marking the corners of one’s property, which is the Mohon. Ideally, these markings are the ones we will place at every corner of your lot for proper identification of your property lines after we surveyed the lot.
However, in some instances such as when the corner lies on an immovable rock or on a living tree, it is improbable that we can place the mohon on that corner. Section 88 of DENR Memorandum Circular No. 2010-13, Adoption of the Manual on Land Survey Procedures, provides for other acceptable lot corner markers such as the following:
- In acceptable living trees – a cross chiselled upon the blaze of an acceptable living tree and at the point of intersection of the cross is a galvanized iron spike;
- In wooden post of durable hardwood of not less than 15cm in diameter forming part of a house, a fence, or other permanent structures – galvanized iron spike set at the center of a cross to be marked thereon;
- In concrete posts, masonry, concrete walls, immovable rock, or boulders – galvanized iron spike driven into the structure or a cross mark chiselled upon such structure, when marking using galvanized iron spike is not feasible;
- In metal pipes having an outside diameter greater than 2 cm – such pipes shall be filled with concrete and shall be defined either by a galvanized iron spike or by a conical hole not exceeding 2 cm in diameter and not less than 1 cm in depth, or by a cross mark chiselled on the concrete top.
In these instances, these markers are accepted as substitutes for the standard mohon. So, if your GE did not place mohon at some corners of your lot for some specific, don’t blame him or ask instantly for a refund. 🙂 Look first for these other markings which s/he could have placed at that specific corner. 😉
- Approved Survey Plans
By LPH LSS
What is an Approved Survey Plan?
An approved survey plan is a survey plan approved either by the Department of Environment and Natural Resources (DENR) or by the Land Registration Authority (LRA). Such plans are considered public documents and can be requested from the approving agencies mentioned.
These plans normally consist of the plotting of the parcel or parcels of land, the survey plan number, the name of the Geodetic Engineer (GE) who executed the survey, the date of the survey conducted as well as the date of the plan’s approval, the technical descriptions of the property, and other pertinent details to identify the subject property’s location.
Use of Survey Plans
Aside from the technical descriptions in the land title, GEs also use the technical descriptions in the approved survey plans as reference in executing their surveys.
If you are a landowner or a would-be landowner, you may also want to request the survey plan of the subject property to know the shape of the parcel of land.
Depending on the region or office where the plan can be requested, the processing of the request for survey plan ranges from one day to two weeks, in some regions, it might take about a month. Its cost also ranges from PHP 20.00 – PHP 400.00 per plan.
To identify the plan number of the property, one can find it in the first paragraph of its land title:
How to determine if the plan is approved?
One can check if the survey plan is approved if such contains the specific survey plan number at the bottom right side of the document, along with the date of approval, and the signatures of the authorized personnel.
Know some of the survey symbols which DENR uses
The DENR is the authorized agency that can approve all types of surveys, both for titled and untitled lands. Here are some of the survey symbols they use in the approval of the plans:
Source: DENR Memorandum Circular No. 2010-13.
If you will engage a contractor in the survey of your property, make sure that s/he is a licensed Geodetic Engineer especially if the survey requires approval either by the LRA or by the DENR for subsequent titling and other purposes.
- Geodetic Engineers’ Tools and Equipment – GNSS
Part 2 By Michael John B. Delos Reyes
On Part 1 of this series, we introduced one of the equipment used by Surveyors in doing land surveys, the Total Station. Now, let’s take a look at another equipment used in land surveys – the GNSS and see its edge over the other equipment commonly used by surveyors and Geodetic Engineers.
The Global Navigation Satellite System (GNSS)
GNSS is a general term that encompasses all types of satellite-based positioning systems. It is a constellation of satellites that orbits the Earth and continuously transmit signals that enable the user to determine positioning, navigation, and timing services on a global or regional basis.
GPS is a type of GNSS. It is a constellation of satellites developed by the United States Department of Defense. There are 4 kinds of GNSS in the world: GPS, GLONASS, Galileo, and BeiDou. GNSS-compatible equipment can use satellites from other networks beyond the GPS system, and more satellites mean increased receiver accuracy and reliability. All GNSS receivers are compatible with GPS, but GPS receivers are not necessarily compatible with GNSS.
GPS and GNSS consist of three segments: the space segment (satellites), the control segment (ground control stations), and the user segment (GNSS or GPS receivers). Some function of the space segment is to receive and store information sent by the ground (control) station and send location information to users in real-time. The control segment is what instructs/performs necessary commands for the space segment and processes all the products for the end-users use. The user segment refers to the GNSS or GPS receiver.
Real-time kinematic positioning (RTK)
RTK is a technology used to improve the accuracy of GNSS positioning. RTK uses one stationary reference receiver called the base station, and one moving receiver called the rover.
Base stations are stationary and their location is known. It is comprised of an antenna, a radio modulator, and an amplifier. The modulator converts the correction data into a radio signal. The amplifier increases the signal’s power, which determines how far the information can travel. The base station calculates its position by utilizing the signals received from the satellites and it is compared to its known location and identifies any errors and generates a correction signal.
The rover is the GNSS Receiver whose location needs to be determined. It utilizes the correction signal from the base station to improve its own calculated position. Rovers can be moved from point to point, stopping momentarily at each new point.
Advantages of Using RTK
The primary advantage of using RTK is that a large number of positions can be established in a short amount of time. It provides centimeter-level positioning accuracy and eliminates human errors caused in traditional surveying. RTK relies on satellite, radio positioning and communication, this makes conducting survey faster. It provides GPS position in real-time and has better waypoint navigation which is required for challenging environments.
If you have projects that would require RTK surveying do not hesitate to contact our team in LPH Land Surveying Services
Allen Instruments and Supplies. (n.d.) Digital and Auto Level Equipment. Retrieved from: https://www.alleninstruments.com/geospatial-solutions/survey-engineering/digital-and-auto-levels/Iqbal, S. (8 July 2021). Digital Level Surveying – Advantages – Component – Types. Retrieved from: https://definecivil.com/digital-level-surveying/
TERRISGPS. (n.d.) GNSS/GPS Differences Explained. Retrieved from: http://www.terrisgps.com/gnss-gps-differences-explained/ Editorial Team – everythingrf. (27 July 2020) What is Real Time Kinematics. Retrieved from: https://www.everythingrf.com/community/what-is-real-time-kinematics
- What is a Lot Plan?
By: Lira P. Habana
One of the most common requirements in applying for a building permit is a Lot Plan. If you are wondering where you can get one, just leave us a message here, and we will get back to you within the day containing the details we need from you in order for us to prepare one. 🙂
So what is a Lot Plan? It is a two-dimensional map containing the plot of your land based on the technical descriptions appearing on your land title, or on the technical descriptions appearing on previously approved surveys conducted over the subject land, or on the actual survey conducted by the Geodetic Engineer. It will provide not only the dimensions of each property line but also the shape of the subject land.
Lot Plans are needed to be signed, certified, and sealed by a duly licensed Geodetic Engineer (GE) for such to be considered valid and with authority. So, before engaging one in plotting the dimensions of your land, make sure that he or she is a licensed GE, as your LGU might require you a photocopy of his/her Professional Tax Receipt and PRC ID, which only licensed GEs will have. Plus, you can be more certain that he or she will produce the output in a professional manner.
- Geodetic Engineers’ Tools and Equipment – Total Station
Part 1 By Michael John B. Delos Reyes
Did you ever see a Geodetic Engineer and wondered what are the instruments they are using? In this article, you will know more about the tools they use to provide quality service.
The most common equipment used by Geodetic Engineers in acquiring spatial data is currently the Total Station along with its accessories – Prism Pole, Prism, and Survey Tripod.
Total Stations are always mistaken for a piece of equipment in photography. Passerby during a survey sometimes strike a pose hoping that the surveyor captures a photo of them but are always disappointed when pointed out that it doesn’t have the capability to take photos.
FUNCTIONS AND FEATURES
A Total Station is a lightweight optical instrument that performs the following functions:
- Distance measurement between two points
- Identify coordinates of points
- Angle measurement
- Display points’ details digitally
- Store data
Total Station surpasses the conventional theodolite by means of having the same function as the theodolite combined with the function of an auto-level and electronic distance meter. The main features that make it a horsepower are:
- All functions are controlled by a keyboard
- The values of distance, angle, height, and coordinates of the observed point are displayed on the digital panel
- The coordinates of the reflector/prism and its angle/bearing can be stored and recalled for the next setup of the instrument.
- If you know the coordinates of a particular point, the instrument displays the angle through which the instrument is to be turned and the distance of the reflector/prism should be moved.
Reflector/Survey Prism redirects a measuring beam back to an Electronic Distance Meter(EDM)/ Total Station which determines the distance of an object to a specific survey point. They are often attached to a prism pole in order for it to focus on a specific position. It needs to be properly aligned with the instrument to ensure accurate results.
Prism Poles are used together with the reflector/survey prism to focus it in a specific location and ensure solid and stable readings.
Survey Tripods are three-legged stands that are designed to provide a stable foundation for the total station and a variety of surveying equipment.
There are other types of survey equipment Geodetic Engineers use in collecting spatial data which depends on the extent or the scope of the project and its duration. If you want to know more about it or would like to avail the services of a Geodetic Engineer, you can reach Lira Perin Habana, founder of LPH Land Surveying Services. She has been a licensed GE since 2014. She is a registered member of the Geodetic Engineers of the Philippines – NCR Chapter (GEP-NCR) and has been consistently providing reliable service to their clients since 2016.
Engineer Supply. (n.d.). Prisms. Retrieved from: https://www.engineersupply.com/prisms.aspx
Engineer Supply. (n.d.). Prism Poles. Retrieved from: https://www.engineersupply.com/prism-poles.aspx
The Constructor. (n.d.). Modern Surveying Instruments and their Use. Retrieved from:https://theconstructor.org/surveying/modern-surveying-instruments-uses/16