Following a Survey with State Plane Coordinates...

coordinates

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> It is highly unlikely that I would draw the figure based on the coordinates given. Mostly because the keystrokes needed for entry of bearings and distances is so much less than the entry of SPCs.?

Also, with bearings & distances you can do a plat closure, which you can't do w/ coordinates.

Around here a survey on SPC would list coordinates for 2 to 4 points, 2 being the required intervisible points. More often than not all the required metadata to get it completely right is not there. Then you kinda guess at which point to start the metes and bounds because it is not always the tract POB.

Also worked along one that had an SPC table for every corner. A few had transpositions, PITA, but more information is always better.

2 years ago I worked on a farm preservation tract South of an already preserved farm. SPC start points and ortho rectified photo makes job planning great. The adjacent survey was only a reference however, I used 3 Z-12s, my 3 ProMark 2s and the other surveyors 4 ProMark 2s on control points, 10 points in one occupation, really sped up the field work. Early this year a different surveyor came off our monuments to put SPC on a tract to the East across the road. Before they were finished we started the adjacent tract to the South along our previous PQ which crossed the road and was adjacent to the new survey. When they came out to set corners they found we had dug out a buried pin they missed on one of their corners and we ribboned it up good. Somebody got bitched out. Long story short they also set a monument along the East side of the road with coordinates that we did not and would not match. All that SPC stuff is just another tool, that not everyone uses well, but it is more important to first find the evidence.

Anyway, assuming I was given a survey with 3 SPC coordinates and 10 bearing distances, I would enter information both ways, then decide what was critical to my adjacent project.

Paul in PA

> It is highly unlikely that I would draw the figure based on the coordinates given. Mostly because the keystrokes needed for entry of bearings and distances is so much less than the entry of SPCs. Is that the general work flow you all tend to employ?

Well, the easy way to do it with my metes and bounds descriptions would be to use OCR software to digitize the coordinate list. It takes virtually no effort to digitize a hundred coordinates that way. Bring those coordinates into CAD and then connect the linework following the metes and bounds description (which is keyed to the point numbers). Too easy. Since the metes and bounds description is also in grid bearings, the bearings inversed between the points will match. If you set the annotation scale factor to the project average Combined Scale Factor used to generate the surface distances in the description, you can check the distances as well. However, if you're matching the bearings all the way around, the coordinates check.

So, what you end up with for virtually no effort is a CAD drawing in SPCS of the tract you're about to survey. Large tracts with lots of courses, particularly so. Download the coordinates to your DC (which will already have the SPCS projection in its library since it's a standard projection) and go find it. Very fast. Very efficient. That's what I'm talking about.

coordinates

> Also, with bearings & distances you can do a plat closure, which you can't do w/ coordinates.

Actually, you use the bearings and distances to check the coordinates. Easier.

For example, here's a list from a metes and bounds description:

[pre]

Point C o o r d i n a t e s
No. N (ft.) E (ft.)

51 10113484.671 3035131.684
52 10113481.334 3035137.459
55 10113802.730 3035141.679
56 10113736.233 3035150.511
61 10113852.718 3035023.985
62 10113729.455 3035040.427
63 10113723.825 3035041.117
66 10113574.768 3034957.002
68 10113842.989 3034974.982
69 10113846.177 3034974.589
70 10113838.826 3035111.763
71 10113575.628 3034955.441
72 10114525.222 3035697.966
73 10114766.387 3035509.559
74 10114964.886 3035236.637
75 10113827.104 3034915.602
78 10113779.102 3034889.430
79 10113657.850 3034803.319
81 10113646.331 3034824.493
87 10113204.095 3035968.363
90 10112990.183 3036064.891
91 10112991.124 3036063.055
92 10113051.870 3035948.151
94 10114832.680 3035418.220
98 10113773.261 3034580.119
149 10113646.589 3034824.150
161 10113924.100 3034834.066
164 10114428.694 3034879.649
224 10114282.799 3035334.923
234 10113693.107 3035147.283
236 10113943.878 3034263.309
237 10112869.013 3036289.002
238 10112904.318 3036307.284
255 10112870.933 3036289.778
256 10112653.827 3036175.935
260 10114384.877 3034875.691
261 10114832.742 3035418.325
262 10114366.204 3035410.211
270 10113969.365 3035185.623
300 10114549.640 3035687.420
301 10114483.490 3035543.550
302 10114445.478 3035483.396
303 10114426.621 3035461.409
304 10114374.680 3035416.170
305 10114350.749 3035404.675
306 10114274.430 3035390.860
307 10114227.731 3035393.525
308 10114154.320 3035415.680
309 10114114.065 3035356.538
310 10114151.030 3035309.750
311 10114135.462 3035251.662
320 10114538.228 3035692.520
324 10114366.471 3035425.595
331 10114130.844 3035263.276
340 10114560.932 3035682.059
347 10114224.119 3035381.560
350 10114160.837 3035317.498
360 10114360.950 3035536.810
361 10114341.844 3035453.870
362 10114256.620 3035489.251
363 10114143.487 3035379.783
364 10114121.608 3035286.505
367 10113952.124 3035178.768
368 10113929.204 3035115.487
369 10113907.034 3035061.684
370 10113882.664 3035038.821
377 10113947.506 3035190.382
381 10113853.038 3035026.393
387 10113956.741 3035167.153
391 10113849.599 3035000.433
392 10113968.748 3035136.956
393 10113896.251 3035097.596
394 10113917.817 3035025.771
395 10113845.169 3035052.740
396 10113867.217 3035133.114
397 10113851.292 3035013.216
[/pre]

Digitizing that from the metes and bounds description via OCR is just about as simple as cutting and pasting the above list, which is in the Texas Coordinate System of 1983 (Central Zone) and belongs to a site near Lake Travis.

I am a little confused by your question. If the survey was given as in SPCS then wouldn't you normally figure that was the truth?

i.e. That the bearings given were grid, and (the rotation defined) and the scale factor defined?

What analysis is necessary? Is your initial assumption that the description is fraudulent? If not would you not take it at face value? If not why?

The very definition of being based on SPCS does not imply ground distances, or other obscure interpretations, it is GRID/GRID!!.

It is clear and concise. Grid distances and grid bearings. No wiggle room for the vagueness that seems to be assumed by your response.

Why is this so difficult?

"I would then check the metadata for the bearing relation and the distances, grid or horizontal/surface."

The 'metadate' is SPCS! The bearing relation is defined for every SPCS grid so why do you have to go into detective mode. This is one of the advantages of the standard 'defined by law' projections. The only metadata required is that it is SPCS based on whatever zone and epoch.

There should be NO detective work required. Now if it doesn't fit you have a few choices. One of which is that the survey description of the datum is fraudulant and you are playing detective to figure it out. Don't then take us on the journey of placing undo reliance on these conclusions. Now that seems to be what we have to do more often than not, but I don't understand the premise of the question.

If the 'bearing relation' was different that SPCS you could note that. but now you are telling me that the survey info you are following is fraudulent in that it is not SPCS, it is unknown crap.

It is either SPCS grid or NOT. The rotation is precisely defined by the SPCS systems. No other rotation should be open for interpretation. Now if the glove doesn't fit we have another discussion.

"If the bearing relation was different, I would apply whatever rotation might be necessary to get the figure to Grid."

So the fact the the definition precisely describes the rotation is meaningless to you? and you are now advocating that everyone 'wing it'?

Give me a break!!

"..then I would apply whatever scale factor needed to be applied to get the distances to Grid..

Again the scale factor if it applies is defined. You do not have to guess.

You have grid coordinates. They yield grid bearings and grid distance. Why do you have to drill down into never never land to assume they are not what they are defined as.

Inverse SPCS coordinates and you get GRID bearing and GRID distances.

Why isn't that obvious??

From there I would translate the figure using one of the called points in the survey to the published SPC for that point.

Why would you rotate from a specified and technically correct basis of bearing? and the same question on origin.

You are telling me that a description which defines a specific datum is just joke and you can translate it to some other assumption with impunity. I say you need to be accountable for that wild assumption.

Again, are you assuming that any description using SPCS is fraudulent?

I don't get your point!!

And finally ..

Mostly because the keystrokes needed for entry of bearings and distances is so much less than the entry of SPCs. Is that the general work flow you all tend to employ?

Oh my GOD you would have to spend 10 minutes entering DATA! Well usually you have both coordinates and then want to analyze the bearings and distances to see if all all holds true.

Isn't this routine stuff? that does not rise to that old saw "it as just tooo..much
work to do it right abd as professional surveyors we should not have to be held to that high standard? What are you saying?

The workflow should be clear to most competent practicing surveyors who understand the basics. I am pretty sure you do, so what is the basis for your questions?

Sit back and figure it out and do it. I just don't get your responses.

- jlw

The real answer is...

use the coordinates as a guide to find the monuments, then locate them.

If we gave the client a metes and bounds description like the one below, they would hire somebody else the next time.

> For example, here's a list from a metes and bounds description:
>
> [pre]
>
>
> Point C o o r d i n a t e s
> No. N (ft.) E (ft.)
>
> 51 10113484.671 3035131.684
> 52 10113481.334 3035137.459
> 55 10113802.730 3035141.679
> 56 10113736.233 3035150.511
> 61 10113852.718 3035023.985
> 62 10113729.455 3035040.427
> 63 10113723.825 3035041.117
> 66 10113574.768 3034957.002
> 68 10113842.989 3034974.982
> 69 10113846.177 3034974.589
> 70 10113838.826 3035111.763
> 71 10113575.628 3034955.441
> 72 10114525.222 3035697.966
> 73 10114766.387 3035509.559
> 74 10114964.886 3035236.637
> 75 10113827.104 3034915.602
> 78 10113779.102 3034889.430
> 79 10113657.850 3034803.319
> 81 10113646.331 3034824.493
> 87 10113204.095 3035968.363
> 90 10112990.183 3036064.891
> 91 10112991.124 3036063.055
> 92 10113051.870 3035948.151
> 94 10114832.680 3035418.220
> 98 10113773.261 3034580.119
> 149 10113646.589 3034824.150
> 161 10113924.100 3034834.066
> 164 10114428.694 3034879.649
> 224 10114282.799 3035334.923
> 234 10113693.107 3035147.283
> 236 10113943.878 3034263.309
> 237 10112869.013 3036289.002
> 238 10112904.318 3036307.284
> 255 10112870.933 3036289.778
> 256 10112653.827 3036175.935
> 260 10114384.877 3034875.691
> 261 10114832.742 3035418.325
> 262 10114366.204 3035410.211
> 270 10113969.365 3035185.623
> 300 10114549.640 3035687.420
> 301 10114483.490 3035543.550
> 302 10114445.478 3035483.396
> 303 10114426.621 3035461.409
> 304 10114374.680 3035416.170
> 305 10114350.749 3035404.675
> 306 10114274.430 3035390.860
> 307 10114227.731 3035393.525
> 308 10114154.320 3035415.680
> 309 10114114.065 3035356.538
> 310 10114151.030 3035309.750
> 311 10114135.462 3035251.662
> 320 10114538.228 3035692.520
> 324 10114366.471 3035425.595
> 331 10114130.844 3035263.276
> 340 10114560.932 3035682.059
> 347 10114224.119 3035381.560
> 350 10114160.837 3035317.498
> 360 10114360.950 3035536.810
> 361 10114341.844 3035453.870
> 362 10114256.620 3035489.251
> 363 10114143.487 3035379.783
> 364 10114121.608 3035286.505
> 367 10113952.124 3035178.768
> 368 10113929.204 3035115.487
> 369 10113907.034 3035061.684
> 370 10113882.664 3035038.821
> 377 10113947.506 3035190.382
> 381 10113853.038 3035026.393
> 387 10113956.741 3035167.153
> 391 10113849.599 3035000.433
> 392 10113968.748 3035136.956
> 393 10113896.251 3035097.596
> 394 10113917.817 3035025.771
> 395 10113845.169 3035052.740
> 396 10113867.217 3035133.114
> 397 10113851.292 3035013.216
> [/pre]
>
> Digitizing that from the metes and bounds description via OCR is just about as simple as cutting and pasting the above list, which is in the Texas Coordinate System of 1983 (Central Zone) and belongs to a site near Lake Travis.

Since a high percentage of surveyors ....

don't know how to properly use & document SPC's, I wouldn't trust anyone else's work until I could verify it by actual location of 2 or more common points. Then attempt to figure out if they did it right. If they didn't, figure out how to make it work.

I NEVER blindly follow anyone else's work - and I wouldn't expect anyone else to blindly follow my work.

I guess I can see the confusion, Mr. Wahl, so let me explain. The rotation and scale factors I'm talking about would be given in the metadata. I'm not assuming that the SPC's are wrong, I'm looking at the metadata to see if the bearings and distances reported are Grid or something else. Our work is typically all reported with geodetic-ish bearings and horizontal/surface distances. Our SPC grid coordinates are true grid coordinates. We then give the mapping angle and brief instruction on how to apply it, as well as the combined scale factor and how to use it. Once or twice, we even held a record bearing and gave a rotation to Grid and Geodetic (not standard operating procedure)

If I have coordinates for ten corners and the bearings and distances between those ten corners, I will enter the plat calls for bearings and distances. I don't enter all ten SPC coordinates. Entering the bearings and distances is faster and provides better error trapping than coordinate entry. Then I'll translate the figure to one of the called SPC's and check that the other nine hit. This was the thrust of my point. It builds on a discussion about LDP's from below.

I'll draw the deed in CAD, translate the corner with a value to it's value, then check the other points in the line work for how they relate to the coordinates reported. If it all checks out, I'll assign point numbers and go hunt them. If not, I'll look at scales and other stuff.

The corner is going to hold, not the value, but I'll have the call versus found. This isn't any different than how I'd look for any corners, other than there is a spatial component to the equation at this point.

that's kind of what I was getting at, Kris. Thanks.

> I'll draw the deed in CAD, translate the corner with a value to it's value, then check the other points in the line work for how they relate to the coordinates reported. If it all checks out, I'll assign point numbers and go hunt them. If not, I'll look at scales and other stuff.
>
> The corner is going to hold, not the value, but I'll have the call versus found. This isn't any different than how I'd look for any corners, other than there is a spatial component to the equation at this point.

Same here.

Sounds right to me Kris. The monuments (assuming undisturbed) hold.

Andy

> If we gave the client a metes and bounds description like the one below, they would hire somebody else the next time.

You understand that list isn't the metes and bounds description, but a note that comes before it? The metes and bounds description is keyed to the coordinate list by point number as in :

> THENCE N62°04’15”W, 256.64 ft. to an old 60d Nail No.91 found in Concrete on the West line of Lohman Ford Road at the South end of a 480.00 ft. radius curve, and taken for the identical “steel pin” described as marking the Southwest corner of that certain 13.5199 acre strip of land conveyed by Mitchell Development Corporation of the Southwest to Travis County, Texas as described in Warranty Deed dated October 27, 1987 recorded in Volume 10605 at Page 375 of the Travis County Real Property Records (TCRPR), same being the true South corner of that certain 13.857 acre tract of land conveyed by Mitchell Resorts, Inc. to CS Golf Management L.C. by Special Warranty Deed dated October 4, 1999 recorded as Doc. No. 1999144339 Travis County Official Public Records (TCOPR),

Is the real problem that folks in New Hampshire like to retype the metes and bounds descriptions that surveyor write instead of simply attaching the surveyor's product to the deed as an exhibit?

Since a high percentage of surveyors ....

:good: :good:

You never know quite what you are getting when someone says "State Plane" -- could be real grid stuff, could be someone's version of state plane "brought up to ground" in all the various ways people do that, like scaling from the center of the project vs. scaling from the origin etc. There's also the innocent little international foot insert unit issue with various CAD programs that will get you if you are working in a u.s. survey foot state.

Sometimes I have had to work with maps where someone has compiled an office survey from a bunch of other maps and mixed grid and ground undifferentiated into something that looks like a survey but doesn't close. Sometimes you can use starnet to puzzle out which are which: Make a grid project, put in the state plane coords, put in the raw measurements if you have them, other map bearing/distances if you don't. If something doesn't close well as grid, try it as measured (ground) & vice versa. If a distance is short, might be grid amidst ground, if it's long, might be measured amidst grid. Bearing differences are a little more obvious, and then there's the rare place where someone subtracts one grid bearing from another and gives a a grid angle, but I've only seen that a couple of times.

You can even drop in some of your own measured data (or GPS) that has a known pedigree and see how the given data matches with it. I did some fieldwork on a project that was "on state plane", but the given coords missed our GPS control net by 3-4 feet. Turned out they had used "ground" on the plans but called it grid. Figured it out by putting their raw data on our own GPS points using this method & discovered that when you raised the raw measurements + our gps points to "ground" it all matched.

Half reporting something that worked and half thinking out loud. Correct me where needed.

very good point, Mr. Bubble.

As Mister Bubble Says...

More often than not, you have to figure it out.

Paul in PA