Raising a State Plane Projection

A State Plane Coordinate System only exists at one level.

You can do anything mathematically you want with it but it no longer is a State Plane Coordinate System.

A State Plane Coordinate System is designed to encompass a large area. A local coordinate system is designed for a much smaller area and can thus be more precise. Precise being used very loosely.

Paul in PA

Spot on, Paul. This approach creates a different projection that shares its central parallel, central meridian, false northing, and false easting with the State Plane projection. What it does not share is the State Plane scale factor on the central parallel, so it is a unique projection with a unique geodetic definition.

I think we are in at least the 4th decade of state plane being shifted to coordinates to use on the "surface". The SOP for the BIG users is to use a simple multiplication of the coordinates by a user defined scale factor and create an error budget to constrain just how "far" this surface coordinate system will allowed to be used.

In the NAD27 days the SMALLER users of state plane would often use ground distances around a point. That point was usually a prominent NAD27 monument and control (other NAD27 monuments) was expanded around it by applying a user defined scale factor and then checked into with traverses that would often use ground distances.

For larger projects state plane distances and coordinates would be calculated and then if needed adjusted by a scale factor, normally around a NAD27 monument holding those coordinates.

However, GPS has seemed to introduce some surveyors to the state plane system that many have used for decades sans GPS and the GPSers seem to have no reference to the hands on use of the system and are uncomfortable with how it's been used for so long.

And I am quite grateful that so many surveyors are uncomfortable with using the system as DOT does, so much work for me because of that.

That's an interesting observation, Moe. When I first learned of State Plane and saw how grid and ground distances were related through combined factors, I thought that the massive computing power available today would make the system easier to use and a more popular choice. However, as you and so many others have pointed out, that is not the case.

Properly used, it's hard to beat.

MathTeacher, post: 380150, member: 7674 wrote: That's an interesting observation, Moe. When I first learned of State Plane and saw how grid and ground distances were related through combined factors, I thought that the massive computing power available today would make the system easier to use and a more popular choice. However, as you and so many others have pointed out, that is not the case.

Properly used, it's hard to beat.

"Properly used..." Very eloquently said!

MathTeacher, post: 380150, member: 7674 wrote: That's an interesting observation, Moe. When I first learned of State Plane and saw how grid and ground distances were related through combined factors, I thought that the massive computing power available today would make the system easier to use and a more popular choice. However, as you and so many others have pointed out, that is not the case.

Properly used, it's hard to beat.

State plane was designed for LARGE uses, quad maps and such, not really suitable for subdivisions, road projects, ect.

And speaking of massive computing power, why not get your coordinates near the surface as best you can instead of adjusting everything else.

Consider a road project with a combined scale factor of .9995. What is the radius of a 1 degree highway curve in state plane for that project? Why bother with all that?

I wouldn't attempt to recommend a projection system to a professional surveyor. As I recall Loyal's post, though, he was asked to create a similar raised plane.

My purpose was to share a method that could be used by anyone who wanted to "...bother with all that," not to recommend that they do it. As to why someone would want to, that is determined solely by their own personal professional judgement.

MathTeacher, post: 380191, member: 7674 wrote: I wouldn't attempt to recommend a projection system to a professional surveyor. As I recall Loyal's post, though, he was asked to create a similar raised plane.

My purpose was to share a method that could be used by anyone who wanted to "...bother with all that," not to recommend that they do it. As to why someone would want to, that is determined solely by their own personal professional judgement.

Personally (and professionally) I see little value in these pseudo-LDP projections, but there is a time and a place for just about everything. Coincidently, I got a call just yesterday morning requesting help generating a Utah-Central-Zone-pseudo-LDP for a friend (PLS).

I understand why different folks want to deal with modern Geodetic Coordinates (and projections) in different ways, and so long as they publish the Datum/Realization/Projection Parameters (constants), OR "modification recipe," I'm a happy camper.

Loyal

MathTeacher, post: 380150, member: 7674 wrote: .... I thought that the massive computing power available today would make the system easier to use and a more popular choice. However, as you and so many others have pointed out, that is not the case..

Of course massive computing power has made it easier to use and a more popular choice, but the problem I run into is many surveyors just using what the magic box kicks out, without the skills or willingness to check that it makes sense. I also try to get guys to go actually measure a ground distance between a couple of points to make sure the actual resulting distances make sense.

Whenever I check someone else's work I get out my calculator and check their math against the "metadata" they publish and see if I get their same results. (No I don't redo a whole network of points but just some spot-checks). The trouble with just calibrating in to their work is that you might just be duplicating their errors. I've seen that happen.

If there is not enough "metadata", I consider that an issue as well.

Is there coursework anywhere that teaches the fundamentals of developing coordinate systems or does everyone learn whatever they can whenever they can?

As a math teacher you should have been exposed to Topology. For others, Topology is the mathematical study of the geometric properties that are preserved through deformations, twistings, and stretchings of objects.

I took a topology course as a Civil Engineering undergraduate at Lehigh University. Besides the basic and advanced Geometry in High school and Geodesy at NJIT.

The short course in SPCs is included in almost every surveying Text.

Satellite Geodesy, the true heart of GPS being a separate course.

It would also be prudent to be well grounded in Physics, not just classical vectors but optical and quantum physics.

Paul in PA

Some of the fundamental constants for Lambert a plane can be developed using algebra, geometry, maybe a little trig, and calculus. When you start to convert angular latitudes and longitudes on the ellipse to linear measures on a plane, however, some higher math is needed. Oscar Adams did it with a complex plane, but other authors use vectors. James Stem "codified" the results so that Lambert planes could be developed algorithmically using his equations without wading through the theoretical development. Of course, he did the same for Transverse Mercator planes, which are much more complicated, as well.

Fortunately, just as you don't need to know how to build a car in order to drive one, you don't need to know how a Lambert plane is developed in order to use it. But some understanding goes a long way if you want to create your own Lambert planes.

MathTeacher, post: 380243, member: 7674 wrote: Some of the fundamental constants for Lambert a plane can be developed using algebra, geometry, maybe a little trig, and calculus. When you start to convert angular latitudes and longitudes on the ellipse to linear measures on a plane, however, some higher math is needed. Oscar Adams did it with a complex plane, but other authors use vectors. James Stem "codified" the results so that Lambert planes could be developed algorithmically using his equations without wading through the theoretical development. Of course, he did the same for Transverse Mercator planes, which are much more complicated, as well.

Fortunately, just as you don't need to know how to build a car in order to drive one, you don't need to know how a Lambert plane is developed in order to use it. But some understanding goes a long way if you want to create your own Lambert planes.

Not to be too much of a stickler for detail, but I take issue with the continued usage of the generic term "plane" when talking about projected surfaces (except of course a "Tangent Plane" and such).

I believe that [at least] some of the confusion many surveyors have with these discussions, is the use of "plane" when we are really talking about a "developed surface," than can be treated as a plane for coordinate purposes, but in fact is a portion of a mathematical SURFACE unique to the particular projection. An Elliptic Cylinder for Transverse Mercator (or Hotine), or a Cone for a Lambert Conic.

Just a pet peeve of mine, carry on.

BTW, I agree 100% with your analogy concerning cars!

Loyal

MathTeacher, post: 380243, member: 7674 wrote: Some of the fundamental constants for Lambert a plane can be developed using algebra, geometry, maybe a little trig, and calculus. When you start to convert angular latitudes and longitudes on the ellipse to linear measures on a plane, however, some higher math is needed. Oscar Adams did it with a complex plane, but other authors use vectors. James Stem "codified" the results so that Lambert planes could be developed algorithmically using his equations without wading through the theoretical development. Of course, he did the same for Transverse Mercator planes, which are much more complicated, as well.

Fortunately, just as you don't need to know how to build a car in order to drive one, you don't need to know how a Lambert plane is developed in order to use it. But some understanding goes a long way if you want to create your own Lambert planes.

Math Teacher I would like to set the record straight (because I like to give credit where credit is due); It was Mr. T. Vincenty who " compiled or developed"
the math for the NOAA Manual NOS NGS 5, State Plane Coordinate System of 1983. Please see said manual page iv and read the first 3 lines under
"ACKOWLEDGMENT". Also look at page 62 "BIBLIOGRAPHY" and you will see listed 3 papers published by Mr. T. Vincenty.
years 1985,and 2 in 1986 dealing with State Plane Coordinate System which were incorporated into NOS NGS 5 which came out in 1989.

JOHN NOLTON

[USER=225]@JOHN NOLTON[/USER] Thank you, John. Thaddeus Vincenty is one of the heroes. His papers are good reads, full of math but always clearly written.

MathTeacher, post: 380243, member: 7674 wrote: Fortunately, just as you don't need to know how to build a car in order to drive one, you don't need to know how a Lambert plane is developed in order to use it. But some understanding goes a long way if you want to create your own Lambert planes.

Good analogy....to further it a bit, you need to know enough about cars to drive them, put in gas, air in tires, how the mirrors adjust, and the more you know the better chances you can figure out what's wrong when it breaks down.....With using a projection, you need to understand enough to drive it through your project....:D

Absolutely, Tom. I think that designing a coordinate system is really the easy part, especially in today's world of boundless software. The hard part is what you and your guys do. But knowing whether an anomaly is likely to be coordinate system-related or measurement-related does make it easier to resolve.

As @Mighty Moe pointed out, knowing the system's error characteristics throughout the project is a key to success. When you look at the documentation for the Iowa system and other similar systems, you see the amount of attention paid to that issue for intensively-used wide-area systems.

Loyal, post: 380245, member: 228 wrote:
Just a pet peeve of mine, carry on.

I hear you, Loyal

Tom Adams, post: 380262, member: 7285 wrote: put in gas

Unless you live in Oregon, where you aren't allowed to pump your own gas...