I'm gonna need coordinates on the drip line of that tree all the way around....looks like you've got it covered 😉
:good:
Masking tape works great for trees.
I can understand the scanner getting very accurate data on objects above the ground such as hills, curbs, trees, buildings, signs, ect. But how does it obtain accurate terrain data when the angle is so flat to the ground?
haha, I was about to post that if you need a lot of trees and topo work, a scanner would be worth thinking about.
having that angle of incidence does hurt your data, no question about it, the further you move away from the gun the less shots you end up getting. But the way it ends up working and the reason it does, is just the sheer number of shots attempted. Throw a couple million shots out, and some will hit blades of grass, pebbles, tiny earthworm mounds, a thousand small things that can add up to a hell of a lot tighter topo than you would collect with a gun. I've never seen a scan have anything like as few shots as a five foot grid.
I did a FEMA project after an ice storm near Sikeston Missouri a few years ago. We were mapping the existing over head power poles. I ran gps control at the beginning and end of the run. My Topcon will reflectorlessly shoot power poles out to 3300 feet. I set the prism constant to +/- half the width of a power pole. As I was setting up Harold, my buddy was going ahead setting a prism pole bipod and traverse point ahead. Then he would drive to the back sight pick it up. I'd be already boxed up waiting. He'd set the back sight as I loaded up, then drive me to the next station. I'd setup again and check some of the poles already shot within hundreds. We were mapping 2 miles an hour taking our time.
Trees - yes, I prefer to leave them out of the DTM. Using reflectorless to get the trees, then collecting ground shots in the open spaces- overall, it's quicker.
why survey 2x for the same point? why not shoot the tree reflectorless near the roots? Set RR ~ 0.05m. That way your tree shots can also be used as a ground shots for the DTM?
> why survey 2x for the same point? why not shoot the tree reflectorless near the roots? Set RR ~ 0.05m. That way your tree shots can also be used as a ground shots for the DTM?
In wooded areas we can't see the ground at the tree roots because of underbrush.;-)
Carpenters measure twice and cut once. We don't cut anything and just keep measuring.
In some areas you can obtain valid ground shots, in others you cannot. That is where the skill of a true measuring master comes into play.
> > why survey 2x for the same point? why not shoot the tree reflectorless near the roots? Set RR ~ 0.05m. That way your tree shots can also be used as a ground shots for the DTM?
> In wooded areas we can't see the ground at the tree roots because of underbrush.;-)
wouldn't it be faster to mark say 1m from the foot of the tree with masking tape on the tree trunk then measure at the tape point & remark the RR = 1 m?
> wouldn't it be faster to mark say 1m from the foot of the tree with masking tape on the tree trunk then measure at the tape point & remark the RR = 1 m?
At what point does it just become faster to get a few ground shots in the open areas?
