Scott Ellis, post: 454873, member: 7154 wrote: What trade secrets? Every survey crew I have talked to can do this, the Lecia salesman even shows you how to do it.
This is how I do my look points, I plot the survey and the adjoiners, I overlay them on an aerial, I guess where I think the property lines are, going by ROW and fences and anything else on the aerial. Go to the location I think will be the best at finding the first corner. Then I just inverse to see how off my look points are. I remember the distance and angle and just in my head move that much for the other look points.
Well he ask "Why would you ever do a localizations or a Site Calibration". I assumed he didn't know why one would do one, so I politely told him why.
Know I don't know why a Surveyor would be Least Squares Adjusting his survey in this day and age. All it does is smear your errors all around mathematically. How would it ever help make a GPS survey more accurate?
roger_LS, post: 454885, member: 11550 wrote: If that's the case, you might as well just use a consumer grade handheld GPS, this would probably get you close enough to find and mark the monuments. Why the fancy equipment?
Because you tie them after you find them with the fancy equipment so you can record a more accurate position in relation to the other corners. Kill two birds with one stone.
billvhill, post: 454882, member: 8398 wrote: I prefer to calculate plats needed for my survey. I reserve a group of points for entered points, plats and calculations usually 1-99, or 1-199 and then begin my survey at 100 or 200. It is just as easy to translate and rotate each group of points then to be changing my GPS points to match the plat. I don't ever have to question whether my coordinates are the problem.
Yep good process. I do the same.
MightyMoe, post: 454878, member: 700 wrote: Calibration was developed to allow the early users of RTK a way of "getting on" older, usually instrument control. It was mainly needed to help with elevations, now Geoid models are far more accurate than any calibration can be.
It became very apparent that calibrations would warp the GPS measurements and wasn't the way to go.
It's become a last resort function only to be used in the most dire circumstance.I see what you are doing, but I would suggest there are much better ways of doing it that don't involve messing with the GPS data, warping it if you will, a two point calibration can do many things almost all of them bad.
I know the salesman sell that function, I think it's been maybe five years or so since the last time I was forced in to applying one.
GPS is a powerful tool, you can put good functional coordinates on the points located using it. These can be projected using an almost infinite selection of choices, all reproducible by anyone following your footsteps. But no one will be able to reproduce a calibration without your electronic file.
Does it really matter? Maybe you will just return the record measurements after finding the monuments.
But for me I want any survey to be on a projection, tied to NGS system with good underlying Lat., Longs., if for no one else then for my use next time I'm in the area (and it's so easy to do these days).
Site Calibration don't really warp your GPS Data. They warp the coordinates your data collector is computing. After you're done finding corners you can remove the calibration and put your tied survey into any coordinate system you want. There's always a way back to your original field measured data. It can be a dynamic process. If an adjacent survey is not fitting you can do a site calibration using points on the other survey. You do have to be careful using more than one point to calibrate because of all the check boxes that have to checked properly ie the scale factor held to 1.00. I've had things go completely haywire using a 4 point calibration so I'm very careful with them. The residuals have to be really low.
When you finish your field survey using a site calibration you have options for setting your basis of bearing. My favorite is to use the GPS derived basis of bearing, but you have the option of setting a basis of bearing to match an old survey's bearing between two monuments. It's good practice to put a Late/Long coordinate on your drawing by the point your GPS basis of bearing is based off of. Nobody around here puts Lat/Long coordinates on the drawing so they would have to have access to your data collector to get that data. An OPUS tied base point in your survey is an excellent idea. The next guy just has to come in set his base on a corner punch the here button and he's already calibrated in to your survey. I've done that a few times, but apparently there's not a lot of Surveyors aware of that capability. One Surveyor in the state started basing his plats on State Plane Coordinates. The sh*t hit the fan. The Utility Surveyors loved it the Family Transfer Surveyors we're up in arms over it.
Bill93, post: 454870, member: 87 wrote: Seems like you have a reasonable search procedure, but a lot of readers initially thought you were talking about real measurements, which need to be done without being distorted by calibrations.
As mentioned above, though, if one of the record measurements is significantly off the calibration can send you searching a longer way off.
Yep, that's why I get the big bucks to recognize those instances and correct them. I plot my search points on aerial photos so I have a pretty good idea visually where to look for pins. The GPS layout refines my search area. I repeatedly amaze my clients by handing them the shovel and say"Dig here". They're amazed when they dig up an iron pin my majic box has found.
Loyal, post: 454822, member: 228 wrote: Why the hell are you "calibrating/localizing" in the first place?
This is Survey 101!
Loyal
I use to use my Silva compass and pace looking for corners. Trust me Loyal this a better way to do it.
Your entire thread is misleading. You've presented a boundary problem but couched it in terms of your gps machine not calibrating properly which makes it confusing and sound like you're not actually doing boundary surveying. Thanks for the survey lesson, dude! Why didn't you just say from the beginning that you wanted talk about how great your approach is and teach all of us your super secret techniques for finding points.
Skeeter1996, post: 454897, member: 9224 wrote: I use to use my Silva compass and pace looking for corners. Trust me Loyal this a better way to do it.
I understand what you are doing, and if it works for you, then great.
I use a similar method, EXCEPT that I use an LDP to "mimic" the Record spatial paradigm (basis of bearing & ground distance). When everything is found, the Record v. Measured Bearings and shown, with NAD83(2011) Epoch 2010.0 Projection Parameters defining the Measured Bearings and Distances, and Latitudes Longitudes (or LDP Coordinates) tabulated for each Corner/Monument.
Loyal
Skeeter1996, post: 454893, member: 9224 wrote: Site Calibration don't really warp your GPS Data. They warp the coordinates your data collector is computing. After you're done finding corners you can remove the calibration and put your tied survey into any coordinate system you want. There's always a way back to your original field measured data. It can be a dynamic process. If an adjacent survey is not fitting you can do a site calibration using points on the other survey. You do have to be careful using more than one point to calibrate because of all the check boxes that have to checked properly ie the scale factor held to 1.00. I've had things go completely haywire using a 4 point calibration so I'm very careful with them. The residuals have to be really low.
When you finish your field survey using a site calibration you have options for setting your basis of bearing. My favorite is to use the GPS derived basis of bearing, but you have the option of setting a basis of bearing to match an old survey's bearing between two monuments. It's good practice to put a Late/Long coordinate on your drawing by the point your GPS basis of bearing is based off of. Nobody around here puts Lat/Long coordinates on the drawing so they would have to have access to your data collector to get that data. An OPUS tied base point in your survey is an excellent idea. The next guy just has to come in set his base on a corner punch the here button and he's already calibrated in to your survey. I've done that a few times, but apparently there's not a lot of Surveyors aware of that capability. One Surveyor in the state started basing his plats on State Plane Coordinates. The sh*t hit the fan. The Utility Surveyors loved it the Family Transfer Surveyors we're up in arms over it.
If you are surveying in Montana I can understand why there are some not liking SPC. It is an awful system, rotations up to almost 5 degrees and scale factors approaching 1' in 1000'. I was helping with a pipeline survey and changing the scale factor for each township crossing going north-south. The pipeline company wanted SPC. Also the state will require it at times. I think DOT and railroads do too.
Loyal, post: 454909, member: 228 wrote: I understand what you are doing, and if it works for you, then great.
I use a similar method, EXCEPT that I use an LDP to "mimic" the Record spatial paradigm (basis of bearing & ground distance). When everything is found, the Record v. Measured Bearings and shown, with NAD83(2011) Epoch 2010.0 Projection Parameters defining the Measured Bearings and Distances, and Latitudes Longitudes (or LDP Coordinates) tabulated for each Corner/Monument.
Loyal
Dr Herb went through a lengthy explanation how to change the parameters of SPC to rotate to a found system. He seemed to prefer doing that.
Me I like it a bit simpler, a nice LDP that is on the same rotation as the found monuments and a scale that will produce ground distances. TM works better with more programs than Lambert.
The parameters are easy to place in a basis statement for any one following to use.
MightyMoe, post: 454913, member: 700 wrote: Dr Herb went through a lengthy explanation how to change the parameters of SPC to rotate to a found system. He seemed to prefer doing that.
Me I like it a bit simpler, a nice LDP that is on the same rotation as the found monuments and a scale that will produce ground distances. TM works better with more programs than Lambert.
The parameters are easy to place in a basis statement for any one following to use.
I also prefer Transverse Mercator.
Most of my work over the years has been in the Great Basin, where (generally speaking) the Mountain Ranges and Valleys run pretty much North-South.
Loyal
roger_LS, post: 454904, member: 11550 wrote: Your entire thread is misleading. You've presented a boundary problem but couched it in terms of your gps machine not calibrating properly which makes it confusing and sound like you're not actually doing boundary surveying. Thanks for the survey lesson, dude! Why didn't you just say from the beginning that you wanted talk about how great your approach is and teach all of us your super secret techniques for finding points.
Well, Loyal asked me why I was even doing site calibrations. So I explained why I did them to him. Loyal is one of the more knowledgeable Surveyors on this Board so I wanted extract his thinking on the subject. THiggins solved my problem long ago. I hadn't held the scale factor to 1.00. Since then the Wolves have come out and it's quite fun discussing things with them. You tend to end up chasing your tail on this Board responding to less enlightened folks. Evidently my super secret system was unknown to some because they don't use site calibrations at all. I haven't been called Dude for a long time LOL. I would be interested in your technical finding original corners without "calibrating" somehow into an old survey. Hopefully your not walking the line with your compass and hip chain.
Loyal, post: 454918, member: 228 wrote: I also prefer Transverse Mercator.
Most of my work over the years has been in the Great Basin, where (generally speaking) the Mountain Ranges and Valleys run pretty much North-South.
Loyal
Loyal you already got me attacked for using site calibrations. I'm not going to bite on you r State Plane bait.
Skeeter1996, post: 454924, member: 9224 wrote: Loyal you already got me attacked for using site calibrations. I'm not going to bite on you r State Plane bait.
I don't get it!
State Plane what?
Loyal
Skeeter1996, post: 454923, member: 9224 wrote: Well, Loyal asked me why I was even doing site calibrations. So I explained why I did them to him. Loyal is one of the more knowledgeable Surveyors on this Board so I wanted extract his thinking on the subject. THiggins solved my problem long ago. I hadn't held the scale factor to 1.00. Since then the Wolves have come out and it's quite fun discussing things with them. You tend to end up chasing your tail on this Board responding to less enlightened folks. Evidently my super secret system was unknown to some because they don't use site calibrations at all. I haven't been called Dude for a long time LOL. I would be interested in your technical finding original corners without "calibrating" somehow into an old survey. Hopefully your not walking the line with your compass and hip chain.
I don't use GPS in this area due to heavy tree cover and relatively smaller projects. Instead use resections off record calcs to get on to the bearing base of a map/deed and find more points. The resection is just to get you oriented than you've got actual side shots to everything. There are places for Compass and tape to get you started.
I trust that the bite wasn't too painful. Your presentation was misleading though, obviously others felt the same way. 🙂
roger_LS, post: 454936, member: 11550 wrote: I don't use GPS in this area due to heavy tree cover and relatively smaller projects. Instead use resections off record calcs to get on to the bearing base of a map/deed and find more points. The resection is just to get you oriented than you've got actual side shots to everything. There are places for Compass and tape to get you started.
I trust that the bite wasn't too painful. Your presentation was misleading though, obviously others felt the same way. 🙂
The newer GPS GNSS gear does work in the trees. Of course you have to have the knowledge to interpret what it's telling you.
I haven't used my Silva Compass since RTK came out. I use my GPS on all sizes of projects. I often wonder how you Stone Age Surveyors would tackle some of my projects. Probably alot of wiggling through the woods stuff. Clearing line that kind of macho stuff. In the Static days we would create mechanical blowdowns so we could get enough satellites to get a position. A few trees died so many could live
Skeeter1996, post: 454924, member: 9224 wrote: Loyal you already got me attacked for using site calibrations. I'm not going to bite on you r State Plane bait.
I'm scratching my head on that one. You may want to try out what Loyal is describing, maybe it would be eye-opening, and since you are using Trimble it's very simple to set up.
MightyMoe, post: 454949, member: 700 wrote: I'm scratching my head on that one. You may want to try out what Loyal is describing, maybe it would be eye-opening, and since you are using Trimble it's very simple to set up.
Loyal changed my initial problem to site calibration s, now he changing it to using State Plane. The wolves are already after to me for the Site Calibration discussions.
MightyMoe, post: 454949, member: 700 wrote: I'm scratching my head on that one. You may want to try out what Loyal is describing, maybe it would be eye-opening, and since you are using Trimble it's very simple to set up.
I'm not familiar with LDP. What does that acronym stand for and who is Dr. Herb? I feel like I came in in the middle of a conversation.
Skeeter1996, post: 454952, member: 9224 wrote: Loyal changed my initial problem to site calibration s, now he changing it to using State Plane. The wolves are already after to me for the Site Calibration discussions.
Skeeter,
Where did I say ANYTHING about "State Plane Coordinates?"
I must be missing something...
Loyal
