Greetings, folks. I have some need for advice from some more familiar than I am with lenghty route surveys or reference material that some of you have found to be good through the years.
I'm doing about 5 miles of a strip topo for a pipeline. My questions mainly have to do with adjusting data and procedures that are put in place before the adjustment (allowing for curvature of the earth). The data will be collected with RTk where possible with the base being from a state network. Wooded areas will utilize total station, with a "mini traverse" ran from starting points set with Gps to ending points set with GPS.
Any help would be greatly appreciated.
Let's hope Kent McMillimeter doesn't find this request.;-)
I don't typically run 3 hour sessions for every ground shot on a 25' grid, but I'm open to the idea. Seriously, if you read this Kent I'll bet you have some good advice. I assure some pretty heavy redundancy on my control. I'm more concerned with others' procedures on defining factors and adjusting large routes of data. There's always more methods that what I know out there that could be faster and better than mine.
Which way are the geoid contours running in regards of the route?
I'd run control / topo in state plane with geoid model, traverse with the gun in state plane, wouldn't worry about curvature and refraction for these small traverses / portages. Then you can adjust to other coordinates system as you wish.
5 miles isn't a very long route survey.
5 miles is not a significant distance for surveying. If you are running rtk in a state plane system, you are pretty much at the length limit while still maintaining a single scale factor.
Set gps control at convenient points along the route, and hopefully you have some nearby benchmarks to tie into. Depending on your gps system and the radio type and terrain, you may have to leapfrog traverse your gps down the route.
Depending in the scale factor, the required precision, and the length of the treed area traverses, you may not even need to deal with grid to ground factors, in transferring gps coords to total station coords. This may be really easy or moderately difficult depending on the software you are running.
A quick "cheat" if you have a bit of flexibility with precision (ie: not laying out 72" steel pipe prefabricated on the other side of the county), would be to traverse through the trees and to just do compass rule adjustment to close out back onto the gps baselines.
That's pretty much my method so far, but let's say 30 miles in length...I understand the adjusting traditional traverses between GPS control, but what are some methods or reference material for determining scale factor? I have so far spaced control at evenly spaced intervals throughout the entire project, however, it's currently along the strip route that changes quite a bit north/south. Some are of the opinion you need control away from the project to create a triangle or square shape to spaced control, even though the route would weave all over the place within that shape....things like that, finding right parameters,etc are what I'm seeking others' methods on.
Kent McMillimeter might teach you something if you pay attention.:-O .
There aren't many texts out there that put what you need in one place. If you are math savvy try Kuang on Optimal Network Design. It's a lot to chew on for most of us. If you are looking for lighter (yet worthwhile) reading try the Oregon low distortion info. Almost everyone can pick up a few tide it's there.
Share a bit about location and we can probably give you better advice. Terrain and projection types dramatically impact your choices...
This project is mostly flat with a gradual slope, but upcoming will be mountainous terrain on next year's project. It's in Tennessee.