When starting a new project that has not already been defined by others (engineers, surveyors, architects), one typically starts at a single point, and coordinates are set for that point (5000, 1000, 100, or whatever).
But as soon as the second point is defined, a decision must be made to align the coordinate system. Assuming a small (<1/2 mile), local survey, what factors (if any) should be considered setting the direction of the coordinate grid? Just get it close to true north? Grid North? Just whatever the direction between the POB and back sight is? Does it matter at all, given that it can be transposed later?
What do most do?
Do What Feels Good Now And Change It Later
On a majority of my jobs the first input are the deed coordinates of the PQ. Next are deed coordinates of adjacent properties. Generally if they do not match the PQ they will be rotated to a common PQ line. Then I may go into the field and resection my field work to the best looking visible monuments. In other cases I may set a field backsight azimuth off the sun and time of day, off a guess if it is just recon to start off a compass bearing. I may GPS some field points during the day or sometimes prior to other field work and get on the GPS SPC coordinates. I do not lose a lot of sleep over it because in the majority of cases I can rotate coordinates in my data collector or the office software with no hassle. Were I to have an ancient deed alongside a filed map parcel I may go to the filed map coordinate system.
If you do not have proper software there is more work involved.
Paul in PA
In the old days before GPS I used to get aggravated with the field crews who were still leaning on the hood of the truck debating how to start the job an hour after arriving. I always told them: Put a nail here, put a nail there, sit here, shoot there, call it north, and we'll figure it out later.
But start doing something!
On many of my small jobs, I will have deeds plotted up, and on some random coordinate system before I head to the field. When I get out there, I will looks for corners, and then start locating them.
I usually have my starting point at 10,000 N and 10,000 E with am assumed elevation of 100.00. I will then take an azimuth reading to my initial backsight point, and then shoot my backsight point, and that will establish the temporary coordinate system and rotation for the job. After I have a few of my corners located, I will translate and rotate my "deed points" to my field shots, and look for additional corners.
After my initial fieldwork is completed, I will download my field data into my CAD software (Carlson Survey 2008 with embedded AutoCAD). I will then rotate to a record bearing, and begin my drafting.
On many of my larger jobs, I will make a trip out there and set up static gps to establish control points while I am looking for corners. I will bring the static gps data in and send it into OPUS, and then post process the data to calculate my control coordinates. I will then upload to the control points into my data collector, and then head into the field.
I hope this helps.
Good luck!
Nearly every project I do is on grid bearings. In our County the coordinates are loosely based on our GIS. Other areas we work on SPC. Assumed coordinates are rare for us.
> Put a nail here, put a nail there, sit here, shoot there, call it north, and we'll figure it out later.
>
> But start doing something!
😀
Thanks all for the comments. I like the simplicity of this one though.
only comment I want to make is the assumed 10000/10000. I am human and have inadvertly imported my northing/easting as easting/northing. Fortunately I have always used two very different numbers for N and E, be it 10000/50000 or 10000/100000 matters not. That way when they are rotated it is immediately obvious.
What Bruce Small said. Hit the ground running, put two control points in and start turning angles. We use RTK with the http://www.keynetgps.com/ network now but only have one unit for that is used by all the crews. If a crew goes out to start a project and the unit is already in use by another everything is on assumed grid and will be rotated up in the office once they have the opportunity to observe two control points for translation.
The previous company I worked for would hit the ground running and then do a loop to the nearest survey control monuments to tie in which would be be drastically more work but would end up with similar results.
Coordinates of additional points.
> When starting a new project that has not already been defined by others (engineers, surveyors, architects), one typically starts at a single point, and coordinates are set for that point (5000, 1000, 100, or whatever).
>
> But as soon as the second point is defined, a decision must be made to align the coordinate system.
Is it true, then, that once you've defined the coordinates for two points in the project (thereby setting the orientation), that upon occupation of the second point, and then turning to a third (or fourth, or fifth, etc.), it does not matter whether you set the BS azimuth to zero, the "real" azimuth, or anything else for that matter, and the coordinates of the following points will all be correct?
Coordinates of additional points.
I always set my backsight on zero and turn angle right directions to all of my foresight points.
I have never surveyed using azimuths. I seem to remember that you might not be using a data collector, so I would have to think about that for a few minutes.
Coordinates of additional points.
> I have never surveyed using azimuths. I seem to remember that you might not be using a data collector, so I would have to think about that for a few minutes.
Your memory is exquisite, sir; I have not been using one until this Christmas, when Santa blessed me with the old Jett XL (which looks like a Carlson Surveyor), that mdriver had for sale here.
I'm somewhat embarrassed to admit I'm considering throwing in the towel on learning how to use the built in Topcon software. I'm withholding final judgement on this, pending how it goes learning SurvCE.
I'm not tossing my field book yet though; I know how to compute coordinates, run traverses, mean results, etc., and don't want to lose touch with what the software is doing.
I'm sure a few test mini traverses will confirm my suspicions; i.e. it doesn't matter what the backsight angle is set to as long as the project has been oriented with two points, but it's been absolutely disgusting this week outside, with snow, sleet, freezing rain and ice pellets; I'm becoming a wimp already.
Coordinates of additional points.
You will like the data collector. The manuals are available on-line if Mark did not have them.
It should work great with your total station. There is no shame in not trying to figure out the onboard data collection software. Most surveyors in the US, and all of the ones I know, use data collectors.
Good luck. There are a lot of SurvCE users here on the board.
When using the total station, I stick two nails in the ground and use a magnetic compass to get a rough backsight azimuth and go for it. No wasted time; I will rotate back at the office. When I use GPS, I use my network rover to set some control points, then switch to total station and keep going. With open sky, it is GPS for most of the work done, and it is super fast.
You may want to look at running your data collector in manual mode and key in an old survey while sitting at your desk. That way, you can work with instrument setup routines and backsight routines. You will need to assign beginning coordinates and decide whether your backsight is a point or an azimuth. Punch in your field notes with a backsight circle set to azimuth or zero and then enter angles right, zenith angles and slope distances. Experiment with horizontal angle offsets and horizontal distance offsets as well as other point location routines and get used to the algebraic signs of your offsets. Go through then do some COGO routines to calculate points. Try some traverse closures and adjustments, intersections, resections, area calculations, and pre-determined area routines, and do some stakeout work to compare to your old survey. Compare your data collector coordinates with your finished survey coordinates. Once you get used to the data collector and its input routines, you can then connect to the instrument in the field and collect raw data as you go, just like your old survey notes in an already familiar format. Also work with some translate and rotate routines.
There are times when GPS is not feasible, so I work with the total station on small surveys under heavy canopy with only a few shots taken with each setup. Too much trouble to take the data collector when surveying solo - the less I have to carry, the better. I still like my hand written notes with sketches and extra notes that are sometimes just too hard to put into a short data field on the collector without sketches. Also, when you get back at to office after a data collected job, switch the collector back to manual mode and input anything else you need, such as supplemental notes in written form. Then you can output computer ready files for your PC. Also work with data import and export routines with the appropriate COM port connections. There is a lot of learning to do in these seemingly simple work routines, but it will be time well spent.
> You may want to look at running your data collector in manual mode and key in an old survey while sitting at your desk.
Thank you for a great Lesson Plan!
When you say "manual mode", do you mean, from the "Equip" menu, "Total Station", "Manual Total Station"? I'd love to get into the mode you're talking about, as the unit really expects to be connected to a total station "live" to do much.
Somewhere in your instrument setup routines, you are able to select the type of instrument to connect. One of your options will be "manual" mode, in that data input will come from the user via keyboard entries instead of an instrument.
I ran TDS for years and now have SurveyPro. One of my instrument types is "manual." I am not sure how your data collector does this. Good luck!
