26/05/2026
USING ONE POINT FOR SETTING OUT ON SITE
( Single-origin coordinate method )
I constantly talk about using only one point for certain setting out operations. Maybe many people do not really understand what I mean, so let me explain it properly.
Let me use the setting out we did yesterday as an example.
On the right side, we needed to maintain 2 meters parallel to the building line from the layout drawing . In the front, we needed 4 meters parallel to the building line. The intersection of the 4 meters and 2 meters gave us our first peg position.
Now, because the 4 meters at the front was more important to us, that became our priority reference for parking space.
If you fix the 4 meters first and then try to square the 2 meters from another peg, you may not get exactly 2 meters. That was exactly what happened on site. Instead of 2 meters, we got about 1.8 meters after squaring.
Why?
Because you were not the one that originally did the layout. The survey plan and the architectural drawing may not perfectly agree with the physical reality on site. This is a common practical site condition many people do not understand until they start real ex*****on work.
So one side may need adjustment.
That is why I always teach a simpler and more practical method:
Use one control peg as your main reference point.
From that one point, square your lines and then compare the remaining dimensions with what is on the layout.
If your critical dimension is correct, you may accept minor adjustments on the less important side depending on site conditions and functional requirements.
In our own case, the 4 meters at the front was the most important because of parking space. That was our priority. So having 2 meters on one side and about 1.8 meters on the other side was acceptable for the purpose of that project because what mattered most was achieving the correct parking clearance in front.
Alternatively, you can maintain 1.9 meters on one side and 3.9 meters on the other side. You can conveniently do this when you are working with one fixed control peg.
Sometimes when I explain these things, people think I am speaking theoretically. No. I am speaking from practical site experience.
On paper, everything may look perfect. But on site, existing land dimensions, survey positions, fence lines, and actual physical conditions may not perfectly match the architectural layout.
That is real construction practice.
If you try to force everything to become perfectly equal without understanding site realities, you may keep moving up and down endlessly trying to correct what cannot practically align.
So what do you do? This applies to any setting out method you adopt.
You identify the most critical control line.
You establish one reliable reference peg.
You square from that point.
You verify the other dimensions.
Then you make practical engineering decisions based on function, site condition, and project priority.
That is practical setting out experience.
Not just theory.