Have you ever gone out to your driveway, looked at your fence, and seen a small square reflector tacked on with a nail? It can be hard to notice, but once you see it you may start to ask yourself: What is that? If you have just noticed that on your fence post, worry not. It is not a practical joke or a spy device. The object in question is likely a survey target.

Let us explain what it is, why it is there, and how it plays a silent, but vital role in your neighborhood’s infrastructure.

What Is a Survey Target?
A survey target is a small reflective maker that is used by land surveyors. They use it when they want to identify precise locations when mapping or constructing. Survey targets can be reflective or adhesive stickers. They can also be nailed on targets through a stake process. This is always done with either crosshair-visible or reflective surfaces. Surveyors use two common devices when a survey target is present: total stations or drones combined with LiDAR. A reflective and/or signal from the survey target enables the total station or drone to identify the precise location.

In the image above, the square survey target marker on the fence post is a prime example of how considerate it is on the face of the marker. By its own size, the survey target is unobtrusive. They are always put on a feature where the surveyor has line-of-sight. Therefore, they must have intended for the target to be there.

Why Is There a Survey Target on My Fence?
If you have found a survey target on your fence post, it was likely done during a survey that was just done, or that you may soon have on your property or in your area. These actions could include:

Widening roads, resurfacing, and other types of roadworks
Installing new services (water, electrical, internet, etc.)
Updating boundary lines or marking boundaries for assets
Municipal development or upgrading neighbourhoods.
Utility company investigations.
Surveyors use these on fence posts, electrical poles, and other things that are securely implanted into the ground. This is done for the most efficient and stable leverage points. That fence post may have been the last reasonably satisfactory anchor point for them.

Should You Be Concerned?
In short – No. These targets are not recording activity, they are not causing any adverse effects, no destruction will take place. They are not cameras, they are not monitors. Think of them as surveyors road signs. They hold no significance. They are low profile, have little role (for determining locations), but are not meant for long term.

You can also always call a local surveying company or public works department in your city to confirm what that target was for.

Can You Take It Off?
Theoretically, you should not take it off; specifically if a licensed professional placed it there permanently for a job being performed by municipalities and utility companies. Though, taking it off may interfere with the project, and shut down or stop work, in your area. After the project is complete, the targets will most likely be removed.

However, if that target has been in position long enough to be extraordinary (most likely way too long). If you see no activity that would signify the project is ongoing, you have the ability to check in with your municipal office or township office and ask if it would be within reason to remove the target.

A Peek Backstage at the Modern Surveying Process
When you come across a survey target on your fence post, or your property in general, think of it like you found a small clue amongst all the other clues. It points to something much larger and complex. This survey target gives a notion of the level of detail and integration in which we build infrastructure. This happens in a country, population, or area. A relatively small number of surveyors connect all the dots together. They build the road networks and lay down the fibre optic cabling. One boring reflective sticker at a time, before we pave over everything.

So next time you see that little box on your property, take a moment of gratitude. For small acknowledgments of little acknowledged work, that essentially shapes mapping, today and into the future. It’s just a little sticker, but it’s attached to something much larger.

Fun Fact:
Surveying is a practice that has taken place as far back as ancient Egypt. Surveyors at that time used ropes with measurements and sticks. Today we have lasers, UAVs, and little reflective targets. These are hard to see and can be temporarily attached on your fence or boundary line. Some things have changed temporally, and some have not. However, the premise for accurately measuring our world is the same.