90% of our work is local coordinates, GPS doesn't work too well in Manhattan.?ÿ Outside of transportation related projects, most projects end up being translated to put a 0,0 coordinate at one of the property corners with the entire site rotated to align with the street grid.?ÿ The 0,0 is typically chosen by the architect during the design process.?ÿ Most of the time they pick the south-west corner but architects being architects, I've seen just about every variation you can imagine, other corners resulting in negative coordinates, flipping 90 or 180 off of north just to keep the street at the bottom of the plans, not actually at the property corner but at some arbitrary offset from the corner, in the MIDDLE of the site, etc.
99% of our surveys are tied to the Texas Coordinate System. Even when we begin with assumed coordinates, we end up on Texas Plane Coordinates eventually, but almost all of our work will pass through city, county or state review and will have to meet their minimum specs.
How do you resolve boundaries while calling North something different than the original survey being retraced??ÿ
It's important to pay attention to the original bearings, but that doesn't preclude using a geographic coordinate system as the underlying basis for your survey. I think too many in the GPS era have confused Geographic coordinates with State Plane coordinates, they aren't synonyms.?ÿ
98%, Like previously stated, why twist and squish a Boundary Survey and make it difficult to use, just so it fits the rest of the world.
98%, Like previously stated, why twist and squish a Boundary Survey and make it difficult to use, just so it fits the rest of the world.
I see it just the opposite. Putting it on a grid bearing basis is going to make it easier to retrace in the future. Putting actual grid coordinates on the corners will further facilitate their recovery.?ÿ
Norman, Exactly my point!?ÿ We have hundreds of section corners already tied and on a state plane coordinate system in multiple counties and states.?ÿ It provides a tremendous boost in efficiency in more ways than I can count.
98%, Like previously stated, why twist and squish a Boundary Survey and make it difficult to use, just so it fits the rest of the world.
I see it just the opposite. Putting it on a grid bearing basis is going to make it easier to retrace in the future. Putting actual grid coordinates on the corners will further facilitate their recovery.?ÿ
Putting lat/long on the corner is just as effective for recovery.
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Putting lat/long on the corner is just as effective for recovery.
Plus the Datum?
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Putting lat/long on the corner is just as effective for recovery.
Plus the Datum?
AND the Realization (epoch etc.).
That SHOULD go without saying. The "origin" of said position (HPGN, HARN, FBN, CBN, CORS, OPUS etc.) should also be included, but aliquot knows all of that, and so?ÿSHOULD everyone else.
The geocentric (ECEF) would work just as well.
I have yet to encounter?ÿ(so far), some numbnuts "modifrickingfying" a Lat/Lon or X/Y/Z coordinate (although I am sure that it has been done).
Loyal?ÿ?ÿ
Metadata is always good to have but a Lat/long or grid coordinate in any flavor of NAD83 should put you within pin finder range. The monument is still king.
One comment against lat/long vs. grid coordinates on a plan. Anybody with a smart phone can navigate to lat/long. Sort of. Lat/long may be more prone to mis-use.?ÿ?ÿ
Metadata is always good to have but a Lat/long or grid coordinate in any flavor of NAD83 should put you within pin finder range. The monument is still king.
One comment against lat/long vs. grid coordinates on a plan. Anybody with a smart phone can navigate to lat/long. Sort of. Lat/long may be more prone to mis-use.?ÿ?ÿ
Another GOOD reason for using ECEF X/Y/Z
Metadata is always good to have but a Lat/long or grid coordinate in any flavor of NAD83 should put you within pin finder range. The monument is still king.
One comment against lat/long vs. grid coordinates on a plan. Anybody with a smart phone can navigate to lat/long. Sort of. Lat/long may be more prone to mis-use.?ÿ?ÿ
Exactly, of course the datum is important, and it ?ÿis always good to include the details, but since coordinates do not hold much legal significance (yet) in North America, they do their job by getting you close enough to find the monument. It could also be argued that providing too much information?ÿalso creates more?ÿopportunities for misuse. ?ÿ
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Putting lat/long on the corner is just as effective for recovery.
Plus the Datum?
AND the Realization (epoch etc.).
That SHOULD go without saying. The "origin" of said position (HPGN, HARN, FBN, CBN, CORS, OPUS etc.) should also be included, but aliquot knows all of that, and so?ÿSHOULD everyone else.
The geocentric (ECEF) would work just as well.
I have yet to encounter?ÿ(so far), some numbnuts "modifrickingfying" a Lat/Lon or X/Y/Z coordinate (although I am sure that it has been done).
Loyal?ÿ?ÿ
You missed the calibration thread?ÿ ??ÿ
Metadata is always good to have but a Lat/long or grid coordinate in any flavor of NAD83 should put you within pin finder range. The monument is still king.
One comment against lat/long vs. grid coordinates on a plan. Anybody with a smart phone can navigate to lat/long. Sort of. Lat/long may be more prone to mis-use.?ÿ?ÿ
We have a requirement that each plat have a SPC coordinate, they have allowed me to put Lat, Long instead. I use the Section corner tie just because of what you mention. Let them calculate the other corners if they want to look. It's all for the GIS guys anyway and the Lat, Long works for them. Lat, Long requirements have exploded the last 20 years.?ÿ
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Been biting my tongue on this for a while but here it goes. Most of the replies to this post boggle?ÿthe mind.?ÿ Of all things one would think would have the most value for being situated correctly on the globe you would think boundaries would be at the top of the list. Surveyors really screwed up?ÿnot being the first to realize and promote this. Not only is it not promoted, it's discouraged by most. Here we are in 2018 and everything imaginable gets assigned geographic?ÿcoordinates except boundary surveys. Come on, man!?ÿ
Do you use that only to record data, or for stakeout, too??ÿ ("East a thousand of a second!")
It's the same as using state plane. East .02' except it is geodetic east and the .02 doesnt need a scale factor. Although, much to the chagrin of my assistants, I prefer meters in the field.
Would not?ÿ .02' in lat/long be an ellipsoid distance? Meaning it would require an elevation scale factor?
I like the idea, just wondering.
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How are boundaries resolved when using State Plane or other Geodetic coordinates. Say you wanted to use a bearing-bearing intersection to create a third position between two found monuments. Would you take a calculator out, apply the difference to the local map and rotate record? Are you first resolving with local bearings then rotating later? Least squared? What is the process??ÿ
Even before I was putting everything on a geodetic bearing relation I still would not use the record bearings to do a bearing-bearing intersection between two diagonal points. I would calculate the bearings of the legs based on the calculated hypotenuse of the diagonal, basically scaling the triangle of the diagonal, leg, leg, from the record to my survey (or if better explained, maintaining the interior angle of the diagonal and legs). I still do that now.
I was doing a survey in a section of land where the DOT surveyor listed state plane for the corner.?ÿ?ÿ Luckily he listed the center-line highway that's how I found out my state plane was 8' off.?ÿ I had to do a rotation to get the right point.?ÿ Sometimes I use state plane but not often.
Resurveying section lines means getting on "true" north. Of course all the locations for sectional surveys can be done in SPC but many calculations have to be done on the bearing basis of the original. If you have to double proportion in a section corner (hopefully not!) that has to be done using true north bearings.
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I was following an old timer from the mid 30's. He worked as a GLO surveyor and moved to the private sector. His worksheets that had all his calculations were in northings and westings. It took me a bit to figure out that they were latitude and departures. He was putting it all on the curve and everything was true north. I suppose if he could do it in 1930 I can do it today.?ÿ
As if on cue an example of the value of putting a job on grid comes to me this morning.?ÿ A small (4 lot) subdivision which I did on the grid 2 years ago. I used the Oregon Coordinate Reference System, Portland Zone - a low distortion projection, but that's for another thread. Nobody asked me to. It's just how I roll. 4 out of 5 local surveyors would have done it on 5000/5000.
The engineer/project manager calls me last night. Way frustrated. He needs to submit as-builts on "City Coordinates". Turns out that "City Coordinates" means Oregon SP, North Zone, NAD83(91).?ÿ No biggy, since the job is on grid already. If it wasn't, it would be. This morning, I'm a hero.?ÿ ?ÿ?ÿ
P.S.?ÿ I'll be value billing this service.