Everything Moves by Stephen C. Corley P.S.

"For the last 25 years, I have been monitoring relative movement on Navigation and Flood Reduction Structures. Our procedures vary from using a T-2 to set a prism pole online and measuring over to the reference mark with a ruler to the nearest 0.01 foot, to using a Wild T-3 on a short forced centering tripod and a target on a translation stage with a machinist micrometer and measuring offset to line of site to the 0.001inch, hoping to get accuracies of +/- 0.01inch.

The high precision surveys with the T-3 and micrometer are at night and are very tedious to perform. Over the years many modifications have been made to the structures such as equipment boxes, guard rails, and winching equipment. As you would guess some of these modifications block our line of sight, requiring us to remove guard rails, cut windows in equipment boxes with removable panels and having to jockey the winching equipment to clear line of sight. 

We have been searching for a better way to perform these surveys but up until recently our big stumbling block has been how to plumb a prism or GPS antenna over the point with an accuracy of +/-0.1 inches quickly. We considered using high precision plummets such as the Wild ZN but the time to set something like that up with that accuracy took too long. We need to measure 80 points per day and we also need the height of prism. We considered some of the mini stakeout poles but to get our accuracies, we would have to keep the prism very low and the obstructions would prevent that. 
Then I saw an advertisement for The Marksman.

We have done some limited testing with The Marksman and have estimated that we can plumb the prism over a point to accuracy of less than 1mm, if we keep the prism on a 1 meter extension or less. Our error budget on the high precision surveys is in the 3mm range so even with multiple setups, as long as we use forced centering techniques of the instrument we should be able to meet our accuracy requirements.

If you do much high precision work such as structural deformation monitoring or as-built surveys on anchor bolts, the basic Marksman is a good tool to have in your tool box. If you do a lot of layout work, the more advanced model with the laser would be very handy.

This is a tool that you may never need to use, but it may be something that allows you to take on new projects that can help your practice. Also, if you do this kind of work, it will make you sleep better at night because you can tell at a glance if your prism is over the point. Most projects that require this type of accuracy also have a lot of liability to them."

Stephen C. Corley P.S.
Licensed in Arkansas, Mississippi and Missouri.


" Two fun projects last week with Van Harten Surveying Inc. and The Marksman Targeting Solutions using our Leica MS50. First was laying-out about 120 anchor bolt locations at 1mm accuracy in a very warm and humid plant. We layed them all out, drilled them, and then checked the holes from setups to verify the accuracy. All in less than 4hrs! Least squares analysis showed that we hit the mark every time. The next day I was on top of an old pier in the Grand River marking out locations for a new pedestrian bridge in Elora. They went in great as well even though I can't hold the camera straight! "

Ron Mak Ontario Land Surveyor Van Harten Surveying Inc. Guelph, Ontario


" I'm very happy with the Marksman for GPS on Bench Mark observations for the 2018 National Geodetic Survey campaign.  The Marksman provides a quick, stable and accurate antenna setup.  It is also very low profile and out of sight, adding to the security of the observation.  With the antenna hidden away the survey crew is freed up to do other work in the area, like recovering adjacent marks or observing on more than one mark along a bench run line at the same time.  Many thanks to you guys for a tool well designed!

Brian S. Fisher, RLS

Arizona State Geodetic Coordinator 
National Geodetic Survey


"I have been using The Marksman Prism Tripod and it is an excellent tool and easy to use especially for a one man crew using a robot. Mr. Gerry Clarke provides excellent service and is always willing to offer great tips to ensure that you are using the tripod the best way possible."

Eric Cronier - Eric Cronier Ltd.,

Grand Cayman


" I use The Marksman XY-001 everyday for all types of Surveys - it is much handier and accurate than a prism pole and/or bipod. It is easy to set up, ideal for indoor/industrial measurements and perfect for high precision measurements. The flexible base legs make it possible to set it on curved surfaces like pipes, and due to its small weight can be easily used on slippery surfaces."

Thomas Gondo OLS

Stoney Creek, Ontario


"We were hired by our client to work alongside their QA/QC department in the construction of a large industrial complex. We were tasked with verification of various structures constructed and machinery installed by multiple contractors on site.

It was our responsibility to insure that the installation followed plans and met the required tolerances, some as small as 1 mm. The use of high accuracy instruments was mandated and we were concerned that achieving the needed accuracy in sighting would be problematic. 

We considered various methods and after seeing “The Marksman” advertised in various trade magazines we decided to give it a try.The Marksman fit the bill, the ease of use and repeatability of shots is wonderful, giving us the confidence that we need.
Enabling us to provide our client with the information they requested and the confidence that the facility was constructed correctly."


Mike Gallick

Chief of Parties

Tri-Tech Surveying Co. LP, Global Surveyors, Inc 

Houston, Texas


"In using The Marksman, it provides a compact system which keep hands free, and yet provide a stabile platform for reliable, consistent, repeatable results. I use it for monitoring numerous high accuracy pins and positions. Being a compact unit allows for faster setups, and quicker changes in positions while maintaning speed without the cost of loss of accuracy."

Norman G. Ribelin 
Ribelin Land Surveying, Inc.
Professional Land Surveyor
Salisbury, NC


"The Marksman is an absolute must for the surveyor looking for a quick, effortless way to layout datum points accurately and efficiently. I'm sure that once you get your Marksman out in the field, you'll find as I did, that the possibilities for making your Surveying tasks simpler and quicker are endless!"

Ralph Braun
Axis Alignment
Grimsby, Ontario


" Throughout September - December 2015 I contracted (who came highly recommended) - Coordinate Control Inc. to layout 71 anchor bolt assemblies @ 800lbs. each not an easy task to set for our new cranes which required high precision. The Marksman made this an efficient project and achieved the necessary precision and really precision is what it's all about! "

Luciano Patricelli

Senior Vice President 
Hans Steel Canada
Uxbridge, Ontario


" The Marksman is a unique tool that has solved several problems with layout and data capture. It has offered us the confidence of one millimeter accuracy for precision Surveying. Hand-held peanut prisms or bipod shots do not provide the accuracy that The Marksman achieves. Investing in precision instruments and neglecting the prism solution was solved by The Marksman. 

No more guessing with multiple samples - with The Marksman you get the same answer every time!"

Tim Verdun
Party Chief
Complete Survey Solutions Inc.
Brampton, Ontario