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Trees in the breeze
About 18 months ago, I updated my aging Geodimeter total station with a much newer, Leica TCRP1205+.
This unit brought me forward several technological generations and allowed me to lighten the rod as well as eliminate all of the cables and external batteries that went with that rock-solid setup.
I very often need to locate and determine heights of power poles, structures and trees. The reflector-less module in this instrument has the same range as the Geodimeter did. My one complaint is that if there is any sort of breeze blowing when I am trying to shoot a tree top, the shots fail. With very few exceptions, the Geodimeter would get the shot under these conditions. The Leica does not.
Is there a technique that a Leica user can use to get this sort of shot? The slightest movement in the leaves or branch that I try to shoot causes the shot to time out and responds with an error message. I have to resort to locating the tree truck and then using a Leica Disto to obtain the height, after the fact.
Perhaps there is a setting or toggle in the Leica that will better handle this type of shot. I generally have the unit in Tracking mode when collecting this type of data.
I am sure some of you have dealt with this issue and I would appreciate to hear any of your solutions.
Thanks in advance for your thoughts.
JA, PLS SoCal
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10 Replies
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This is not exactly what you are asking for, but if you are shooting the trunk and can see the top by turning a vertical angle, there is likely a routine called something like ??remote elevation? or ??trig? that would avoid a return visit with the disto.
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Jerry, I think the Leica reflectorless is a one speed type of deal. I don’t think there is a Coarse-Normal-Fine option for this. The reflectorless shots take a bit longer, and iirc it was something like 1.5-2 seconds fromm the specs sheet.
There’s a beam divergence with the 1200 series ~0.2′ in 600′.
If you get to the limits of your reflectorless specs, this makes it harder. -
Also pg 117-units and formats-v angle fixed or running, with v angle running you can turn up or down after getting a distance and the elevation will update until you record the shot.
You probably want to make units and formats a shortcut in the user function, it is really handy.
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I am not sure if it applies to reflectorless shots but quite often I change the settings to FAST.
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It does not, the higher range RL guns work better even below the distance threshold though, Jerry did not say what the rating is but the lower ones can be pretty frustrating.
I do not think that higher angular precision is necessarily what a person should spend money on but firmly think the extra RL capacity is worth while.
Looking at the OP I would turn tracking off, that way if you get a good one in the mix you do not have to worry about it getting blown off with another distance shot.
Be aware of the shift user menu, it is pre-set unlike the user menu but has some good options in there and leaves more slots in the user menu if you do not have redundant options.
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Jerry, I think the problem you are running into has to do with beam width. Leica’s reflector less beam is very narrow comparatively and the tree tops are moving out of the path before a distance is achieved. The tree top has to move a greater distance to be missed by a wider beam. When I run into this situation I try to track the tree. If that fails you can set the instrument to not hold the vertical angle after a shot then shot a little lower on the tree, just enough to have a more solid target, then when the measurement is achieved, aim to the top and store the point.
While the narrow beam is a pain for moving targets, it is great for accuracy. You should also check to make sure the RL is correctly adjusted to the cross hairs. It is nice to have the laser hit the mark. I think the reference manual goes into great detail on this.
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Shoot ground at tree trunk and record vert. angle at the top. I usually do 2 shots 1 for the hz location of the tree on the ground and another vert. ang. offset for the height of the tree.
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Thank you to all whom responded. I now have a few things to test to see if I can get what I want. Some of your instrument knowledge is awesome!
Thanks, Wendell, for curating this site. I knew that I would get some great information.
JA, PLS SoCal
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