Best GCP Target Size for Drone Survey Malaysia – 50cm vs 100cm vs 150cm by GSD
Best GCP Target Size for Drone Survey Malaysia – 50cm vs 100cm vs 150cm by GSD
Content
Best GCP Target Size for Drone Survey Malaysia
How to Choose 50×50cm, 100×100cm or 150×150cm Ground Control Point Targets Using GSD
One of the first questions from a drone surveyor buying Ground Control Point targets is:
“What size GCP should I use for my drone?”
Many buyers try to choose based only on flight altitude.
For example:
50m flight = which GCP?
100m flight = which GCP?
120m flight = which GCP?
But there is a better way to think about it.
LOOK AT GSD — NOT FLIGHT ALTITUDE ALONE.
MTM Precision supplies reusable GCP targets in:
• 50 × 50cm
• 100 × 100cm
• 150 × 150cm
QUICK ANSWER: 100×100cm is our practical general-purpose starting option. Choose 50×50cm where the smaller target remains clearly identifiable, and consider 150×150cm where additional visual footprint is beneficial. The correct choice depends on GSD, camera, flight configuration, contrast and ground conditions.
What Is GSD?
GSD means:
GROUND SAMPLING DISTANCE
In simplified terms, it describes how much ground distance is represented by one image pixel.
For example:
2cm/pixel GSD
means approximately:
1 image pixel represents 2cm on the ground.
Smaller GSD generally means finer ground detail.
Why Does GSD Matter for GCP Targets?
A GCP must be identifiable in the aerial imagery.
Suppose you use a 100cm-wide target.
At:
2cm/pixel
a simplified calculation gives:
100cm ÷ 2cm/pixel = approximately 50 pixels across
At:
5cm/pixel
the same target becomes:
100cm ÷ 5cm/pixel = approximately 20 pixels across
Same physical target. Different image footprint.
That is why GSD matters.
50cm vs 100cm vs 150cm at 1cm GSD
Simplified ideal geometric comparison:
Target SizeApprox. Pixels Across50×50cm50 pixels100×100cm100 pixels150×150cm150 pixels
At this GSD, all three targets occupy a relatively substantial number of pixels in this simplified calculation.
But actual identification also depends on image quality and target contrast.
50cm vs 100cm vs 150cm at 2cm GSD
Target SizeApprox. Pixels Across50×50cm25 pixels100×100cm50 pixels150×150cm75 pixels
This shows why a larger target can provide more visual presence.
It does NOT mean the 150cm target creates three times better survey accuracy than the 50cm target.
50cm vs 100cm vs 150cm at 5cm GSD
Target SizeApprox. Pixels Across50×50cm10 pixels100×100cm20 pixels150×150cm30 pixels
At coarser GSD, the smaller target occupies fewer pixels.
This can make reliable identification of the exact reference point more challenging.
Simple GCP Pixel Formula
A useful conceptual calculation is:
TARGET WIDTH ÷ GSD = APPROXIMATE PIXELS ACROSS TARGET
Example:
100cm target
÷
2.5cm/pixel
=
40 pixels across
This is a simplified geometric estimate.
Actual image appearance can be affected by:
Motion blur
Focus
Lens characteristics
Viewing angle
Lighting
Target condition
Image resampling
Processing
Why We Do Not Give a Universal “100m = 100cm GCP” Rule
Because altitude alone does not determine image scale.
Two drones flying at exactly 100m may use different:
Sensors
Image resolutions
Focal lengths
Lenses
Camera modes
Therefore, they can produce different GSD.
SAME ALTITUDE ≠ NECESSARILY SAME GSD
This is why target recommendations based only on altitude can be misleading.
50×50cm GCP – When Should You Choose It?
BEST ADVANTAGE: PORTABILITY
The 50×50cm target is compact and convenient.
Consider it where:
✓ Planned GSD provides sufficient target visibility
✓ Flights produce detailed imagery
✓ Project area is manageable
✓ Field teams need to carry many targets
✓ Portability is a priority
50×50cm can be perfectly useful when the imaging conditions make it clearly identifiable.
Do not reject it simply because it is smaller.
100×100cm GCP – Why It Is Our General-Purpose Choice
BEST BALANCE: VISIBILITY + PORTABILITY
The 100×100cm target sits between the compact 50cm and large 150cm options.
For many general projects it provides a practical compromise.
Applications include:
Construction
Earthwork
Topographic mapping
Road projects
Quarry mapping
Plantation
Land development
If the customer does not yet know which size to start with, 100×100cm is normally the first size we would evaluate.
150×150cm GCP – When Is Bigger Useful?
BEST ADVANTAGE: LARGE VISUAL FOOTPRINT
Consider the 150×150cm target when:
✓ Additional visual presence is desirable
✓ GSD is relatively coarser
✓ The mapping area is large and open
✓ Ground texture makes smaller targets harder to identify
✓ Project conditions justify the additional physical size
However:
BIGGER DOES NOT AUTOMATICALLY MEAN MORE ACCURATE.
Why Not Always Buy 150×150cm?
If bigger targets are easier to see, why not use the biggest one for everything?
Because field practicality also matters.
Larger targets require:
More storage space
More carrying space
More deployment area
More handling
For teams deploying many GCPs:
The best target is not necessarily the biggest target—it is the smallest practical target that remains reliably identifiable for the required workflow.
Target Centre Visibility Is More Important Than Seeing “Something”
It is not enough to say:
“Yes, I can see a black-and-white spot.”
For GCP marking, you want to identify the intended reference point consistently.
That means:
Pattern clarity matters
Image sharpness matters
Pixel footprint matters
Contrast matters
The objective is reliable reference-point identification—not merely detecting that a target exists.
Contrast Can Change the Result
Consider a target on:
Dark Asphalt
One portion of the target pattern may visually blend more with the background.
Light Concrete
A different portion may have reduced contrast.
Red Soil
The black/white target may stand out strongly.
Grass
Vegetation can partially obscure the edges.
Target size and target contrast should therefore be considered together.
Image Blur Can Make a Large Target Harder to Mark
Pixel count is not the complete story.
Even a target occupying many pixels can be difficult to mark if the image suffers from:
Motion blur
Poor focus
Strong shadow
Obstruction
Overexposure
Poor viewing geometry
PIXELS ALONE DO NOT GUARANTEE A GOOD GCP IMAGE.
Target Orientation & Flatness Matter
A target should ideally remain sufficiently flat and visible.
If it is:
Folded
Wrinkled heavily
Partly covered
Positioned on an extreme slope
the pattern may become harder to interpret.
Good target deployment is part of target visibility.
Does a 150cm Target Improve Accuracy Over 100cm?
NOT AUTOMATICALLY.
Suppose both targets are already clearly visible and their centres can be identified reliably.
Changing from 100cm to 150cm does not automatically improve:
GNSS coordinate accuracy
GCP measurement accuracy
Drone RTK accuracy
Camera calibration
Flight geometry
Processing quality
TARGET SIZE PRIMARILY SOLVES A VISIBILITY PROBLEM.
What Actually Affects Drone Mapping Accuracy?
The complete system matters.
Important factors can include:
1. GCP Coordinate Quality
Poor surveyed coordinates produce poor control.
2. GCP Distribution
Control should appropriately represent the project.
3. Image Quality
Sharp, properly exposed images matter.
4. Flight Geometry
Image overlap and acquisition design matter.
5. Camera & Calibration
The imaging system influences photogrammetric reconstruction.
6. GNSS / RTK Performance
Positioning quality matters.
7. Processing Workflow
Correct configuration and image marking are essential.
8. Independent Check Points
Useful for evaluating the resulting mapping.
GCP TARGET SIZE IS ONLY ONE PART OF THE ACCURACY CHAIN.
Which Size for Construction Drone Survey?
Recommended starting consideration: 100×100cm
Why?
Good general visual footprint
Practical field handling
For larger open sites or where additional visibility is needed:
Consider 150×150cm.
Which Size for Quarry Drone Survey?
Quarries often have:
Complex ground texture
Dust
Large areas
Elevation variation
For general applications:
Start by evaluating 100×100cm.
Where greater visual presence is beneficial:
Consider 150×150cm.
Which Size for Plantation Drone Survey?
Plantation environments create vegetation-related visibility problems.
100×100cm is a practical starting point.
But remember:
A 150cm target hidden under tree canopy is still hidden.
Placement can be more important than simply increasing target size.
Which Size for Road Survey?
Road corridor projects can require multiple targets spread across substantial distances.
Field portability becomes important.
Depending on GSD:
50×50cm → highly portable
100×100cm → balanced option
150×150cm → larger visual option
Select according to both image visibility and field logistics.
Should I Buy More Than One Size?
For drone survey companies handling different project types:
YES, A MIXED-SIZE GCP KIT CAN BE PRACTICAL.
For example, a team may use compact targets where imagery provides sufficient resolution while keeping larger targets available for sites where greater visibility is required.
But:
Maintain a clear, consistent definition of the surveyed reference point regardless of physical target size.
GCP Size vs GCP Quantity
Do not confuse these two decisions.
TARGET SIZE
Main question: CAN I SEE AND MARK IT RELIABLY?
TARGET QUANTITY & DISTRIBUTION
Main question: DOES MY CONTROL DESIGN SUIT THE PROJECT?
They solve different problems.
SIZE = VISIBILITY
DISTRIBUTION = CONTROL GEOMETRY
Common GCP Size Selection Mistakes
MISTAKE 1 — Choosing Only by Flight Altitude
Use GSD and imaging conditions instead.
MISTAKE 2 — Assuming Bigger Means More Accurate
Bigger mainly improves visual footprint.
MISTAKE 3 — Choosing the Smallest Because It Is Easier to Carry
If you cannot reliably mark it, portability does not help.
MISTAKE 4 — Ignoring Ground Contrast
A target must stand out from its surroundings.
MISTAKE 5 — Looking Only at Pixel Count
Image quality also matters.
MISTAKE 6 — Confusing Target Size With GCP Quantity
They are separate survey-design decisions.
Quick Buying Guide
Your PrioritySize to EvaluateMaximum portability50×50cmGeneral-purpose drone survey100×100cmLarger visual footprint150×150cmConstruction / Earthwork100×100cm firstLarge open quarry100×100cm / 150×150cmPlantation / Agricultural100×100cm / 150×150cm depending on visibilityMultiple project typesConsider mixed sizes
These are practical starting considerations—not universal engineering rules.
Frequently Asked Questions
What is the best GCP target size for drone mapping?
There is no single best size for every project.
For general-purpose use, 100×100cm is our practical starting option.
Is 50×50cm too small?
Not necessarily.
If it remains clearly identifiable at the project's GSD and under actual imaging conditions, 50×50cm may be suitable.
Is 150×150cm more accurate?
No.
It is physically larger and therefore provides a larger visual footprint, but target size alone does not determine survey accuracy.
Should I choose GCP size based on drone altitude?
Altitude is relevant, but GSD is more directly useful for estimating the target's image footprint.
What GCP size should I buy first?
For a survey company wanting one versatile size:
100×100cm is the practical starting choice.
Buy 50cm, 100cm & 150cm GCP Targets in Malaysia
MTM Precision supplies reusable Ground Control Point Targets for Drone Survey and UAV Mapping in Malaysia.
Available Sizes
50 × 50cm — COMPACT
100 × 100cm — GENERAL PURPOSE
150 × 150cm — LARGE VISUAL TARGET
Suitable for:
DRONE SURVEY
UAV PHOTOGRAMMETRY
CONSTRUCTION
EARTHWORK
TOPOGRAPHIC MAPPING
QUARRY
ROAD & HIGHWAY
PLANTATION
LAND DEVELOPMENT
Contact MTM Precision
MTM Precision Sdn Bhd
Website: www.mtmpre.com.my
Email: mtmpre@yahoo.com
WhatsApp: 016-660 7346
Showroom & Service Centre
No. 29-1 & 29-2, Jalan Bandar 18,
Pusat Bandar Puchong,
47160 Puchong, Selangor, Malaysia.
Supplying GCP targets, drone survey accessories and professional surveying equipment throughout Malaysia, including Selangor, Kuala Lumpur, Johor, Penang, Perak, Negeri Sembilan, Melaka, Pahang, Kedah, Perlis, Terengganu, Kelantan, Sarawak and Sabah.
08 Sep 2026
