Hello, hopefully it is alright to be posting this here.
I'm currently beginning a research project for a M.Sc plant science and part of this research will look at how crop productivity changes, as elevation changes, across variable terrain. My goal is to run a transect- imagine a long measuring tape- and at set intervals of the transect I will take various crop productivity measurements like plant biomass, soil nutrient status etc. The transect will be run from an area of low elevation to an area of high elevation in an effort to understand how crop productivity changes as elevation changes in farm fields. I need an accurate method of measuring what the elevations are in the field along the transect. So far I have narrowed it down to a rotary laser level, a robotic total station, or a GNSS system. I would love to hear what you folks think may be the best option. I would like it to be relatively simple, cost-effective, and accurate.
Thank you,
Will
I would just use an auto-level and take the distance measurements using stadia. Cheap and accurate.
How long is your proposed transect?
Does your university have a surveying or civil engineering program? If so they may have all the equipment you'd need, and you may be able to either borrow it or get someone to collect the needed data for you. If not, it would probably be more cost effective to get a local surveyor to collect the data for you than to buy or rent the equipment and then learn now to use it.?ÿ
A hand level on a shovel stuck in the ground, 12' fiberglass level rod and 300 foot vinyl tape.?ÿ OR?ÿ Handheld GNSS and a smartphone.
I am assuming there is a very steep gradient along the transect you are using.?ÿ Perhaps something similar to the terraced farmland of Peru in the Andes Mountains.
I took a class in Physiology of Farm Animals that included discussion of certain issues that can occur in livestock due to long term exposure to high altitude.?ÿ One item I recall after more than 40 years is that male sheep can become sterile if kept above a certain elevation for a long period of time.
Am interested in what is being anticipated for differences in production levels in your study.
A single setup with a total station where both ends of the transect are visible and within the limits of the machine might be all you need to do.?ÿ One shot at each end of the transect providing the horizontal distance, the vertical distance and the slope between the end points.?ÿ Later, you might take shots on specific locations along the alignment of your transect to document where certain changes were noted.
You would receive better advice if we know how long, how much elevation change, whether it's open sky or forest or orchard, does this need to be related to an elevation datum?
You've gotten some good suggestions, but based on various assumptions that may or may not hold.?ÿ To get the best advice you need to specify the elevation range, the desired elevation accuracy, the overall distance, the typical distance interval between elevation measurements, whether there is a clear line of sight over that whole distance, and whether the distance is along a straight line.
You mention a GNSS system, but what do you have available? There are many ways to use GNSS and the accuracy and field time will vary depending on whether it is a single receiver, a pair of receivers, a receiver and correction network connection, the distance from a reference station, etc.
Edit: like Dave said ...
A basic total station, and a rodman?ÿ
horizontal distance, elevation difference right on screen. Unless the line of sight is overgrown. But farm land is generally easy. Taking dozens of shots along 10 ft wide swath and someone could easily contour it.?ÿ
You would receive better advice if we know how long, how much elevation change, whether it's open sky or forest or orchard, does this need to be related to an elevation datum?
Also the degree of precision required. It might be that google maps, a smart phone, and an altimeter would be sufficient.
