There's a table of temperature corrections on our digital level rod. I wouldn't think a fiberglass (?) rod expands or contracts. Does this correction address the movement of whatever kind of light beam the digital level uses, through the air?
No, the instrument functions like a camera, not an EDM.
I have never seen that, but I would assume there is some expansion/contraction if they put it on there.
The table on the level rod, is the temperature correction for the fiberglass level rod.
That's why some use an Invar Rod.
Invar also has a coefficient of thermal expansion for it as well, but, you are really smashing gnats with sledge hammers at that point. Just something to keep in mind if you are at the extremes
If it functions like a camera, does that mean the amount of rod it photographs is smaller than the area I would need to manually read three wires? I was running the rod yesterday, and I was considering how much rod the level needed to see. The party chief mentioned the level uses a smaller viewing area when it reads the rod.
Field Dog, post: 456898, member: 9186 wrote:
I remember running 2nd order levels for a few cities in the area using invar rods and the such, and we were lined out to make sure not to go under 1 meter or above 2 meters for accuracy purposes. I was under the impression this was because of the camera not fully being able to read the barcode correctly.
I know with the Leica DNA levels and FG rod you can definitely get a reading electronically where at least some of the view is above or below the rod, probably has some accuracy limitations, HOWEVER I have never noticed any issues in running short loops for engineering type elevation transfer surveys. I am pretty sure for tight geodetic type work that isn't best practice, but it will read the rod within limits even if not a full rod view.
SHG