Any recommendations for survey target stickers for surveying inside warehouses etc?
Berntsen has some interesting targets that they are producing...
http://www.berntsen.com/Surveying/Smart-Targets-Datums-Reflectors
> Any recommendations for survey target stickers for surveying inside warehouses etc?
For having crap parked on line, or on top of your control points, surveying in an active warehouse is like the worst construction site you've ever been on x100. It doesn't matter where you put your stickers, something massive and immobile will be put in front of them the minute you turn your back.
You might get lucky, but plan on bringing control in from outside on every visit.
I learned a neat trick
We participated in a job a while back where we were using tape targets. But what was used was just plain colored tape cut into 2" squares. When they were mounted they were set in a diamond orientation rather than a square orientation.
When taking your sight you didn't worry about the middle, rather you put your horizontal cross hair on the left point and your vertical cross hair on the top point. The repeat ability was extremely tight using prismless.
:good:
I've used those targets on a bridge job. We set them on many of the piers of the existing bridge and resected from them while constructing the new bridge. I brought along an extension ladder and set them up as high as I could. Never really had a problem with equipment in the way and our results were fantastic.
Aside from some of the links below, I have heard of some making their own stickers from the same reflective tape found at truck stops that are for semi trailers.
I would just do a couple tests to ensure you know what the offset of the tape is before you hang your hat on it. Should be zero but you never know.
Maybe Radar will join in. He sent me some that he had made out of dots stamped out of several different types of reflective tape. I took a hole punch and punched out the centers and stuck them on some composite utility poles on a job last summer and they are still there.
Set a bunch of them on secure locations at 0 offset. Resect yourself back in at any location you want at 0 offset. That way, you eliminate the need to bring control back in and also setting up backsites and the error associated with it.
There's two basic types of reflective tape.
The Scotchlite stuff is comprised of tiny spherical glass beads on top of aluminized substrate. That will return a light beam ONLY about ±60º to 90º. (It's the traditional stuff used on bicycles for over 50 years.)
Scotch, Reflexite, and others now make a retro-reflector type of tape that actually has micro corner cubes covering the surface and will return a light beam about ±17º to 90º and is significantly superior.
I purchase the stuff in bulk and use different types of hole punches to fabricate my own targets. There are hobby punches that will make 1-inch circular targets as well as various other larger sizes. A little ingenuity goes a long way with this stuff, and there is a variety of colors available, too. Easy to find sources with Google.
My new total station (Topcon ES105) has a mode for target sheet. I use it with the reflexite. I have compared it to a prism and it is just as tight. It is amazing at how well it works.
> Maybe Radar will join in. He sent me some that he had made out of dots stamped out of several different types of reflective tape.
How'd those work out for you?
I've only had a few jobs that required mulitple visits, so I haven't been able to use them very often.
I did a 3/4 mile staking job; storm drain, water, curb gutter and sidewalk. It was a very narrow corridor; lots of equipment, piles of material everywhere. It was nice having 37 targets all over, that I could resect from. Very tight, always checked existing and control points on the ground within 0.02'.
I'm sending Brad some today, anybody else care to check them out for me?
Email in profile is good.
You're Welcome.....;-)
B-)
Radar
> There's two basic types of reflective tape.
>
> ... tiny spherical glass beads ... ±60º to 90º
>
> ... micro corner cubes ... ±17º to 90º
Good to know, thanks.
Are there specific brand names or generic names that definitely distinguish between the two, or must one always study the specifications/descriptions?
I was going to wait until they went thru 4 seasons before reporting, but so far so good. The scaly ones seem to work better than the other ones, but all the ones I used are still in. I've got one pole that seems to be waltzing around, but other than that all is good. I appreciate it.
Can't go wrong with Reflexite brand. There's a special trade name for the Scotch stuff, but I do not know that name. Commonly the distributor will have an illustration of the product that's magnified and it's pretty easy to recognize from that.
I found out about the stuff when I was working on a project for the Naval Research Laboratories doing close-range digital photogrammetry for shipbuilding applications.
> I was going to wait until they went thru 4 seasons before reporting, but so far so good.
Thank you Randy; a 12 month trial sounds like a good idea, I never thought about weathering. I look forward to seeing what you find. The ones I put up are still there and it's been over 18 months. I'll have to stop and take a look at them close up, the next time I'm in that area.
> The scaly ones seem to work better than the other ones.....
What makes them better?
> I've got one pole that seems to be waltzing around, but other than that all is good.
I had trouble sticking them to creosote poles; I roughed them up with sandpaper then cleaned them with a clorox wipe. That seemed to make them a little better.
> I appreciate it.
You are welcome....:-D
No problem.....;-)
Any time.....B-)
Doug
Cliff,
I went to www.orafol.com which owns the Reflexite brand. It is indeed "microprismatic" but i couldn't see any angular specs.
At solutions.3m.com there there were 2 or 3 kinds of tape, "highly reflective, even up to 90 degree angle". (I assume the only way to restate that via your angle-specs method is that it is "±45º to 90º"?) They have
- Scotchlite reflective material – "transfer films ... wide angle, exposed retroreflective lenses..."
- Scotchlite reflective material – "high gloss ... highly retroreflective microprisms..."
- 3M™ Diamond Grade - also microprismatic
Even the detailed specs are still hard to compare with yours:
The coefficient of retroreflection values are
- "at 0° orientation, 5° entrance angle and 0.2° observation angle"
- "are averages of readings taken from rotation angles that are 90 degrees apart"
And "The 0° rotation angle is to be taken as the down web direction of 3M supplied rolls"
Not that this is any reflection on your capabilities at providing useful info, Cliff, is anyone else willing to cast new light on the subject, possibly from a new angle? :cat:
At longer distances the scaly ones will return a distance on my S6 in standard tracking mode, where I have to switch to direct reflex on the other ones.
I've played with "Reflective Safety Tape" strips made by Hillman Sign Center and sold by Home Depot. A package has 2 red and 2 white strips 6" x 1 1/4" for a few bucks. They have the scaly prism surface.
With an EDM that gets a mile on one 3" glass prism, the max range for one of these strips is about a hundred yards. I haven't tried a smaller piece, but would expect a good fraction of that because range is a weak function of reflector area. I haven't done much testing off axis.
Nearest operating range on those strips is about 10 ft, although I don't fully understand that limitation. It looks good by eye with a flashlight at closer range.
The Hillman 3" plastic "mailbox post" reflectors are good past 400 ft with this EDM. Other brands have worked, but not all to that range. The 1-1/4" circular Hillman and Cole reflectors are not useable due to a different scattering pattern.
Would anyone mind sharing their procedures/best practices of setting/using these targets, or any literature on the subject. This seems like the solution we need for many of our construction projects, but not having used them I'd like to know the proper techniques in setting them along with other do's and dont's. Thanks.