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State Plane Coordinate System of 2022  

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Shawn Billings
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April 15, 2018 3:19 pm  
Posted by: aliquot

There is no reason to continue using state plane coordinates. Today's software can easily handle the real curved surface of the earth. We don't need these approximations that were developed when calculations had to he done by hand anymore.  

I'm all in favor of that transition, but the fact is that most of our software does NOT work well with geodetic coordinates. I'm unfamiliar with any CAD software that works this way (although I would be happen to be proved wrong!). I work for Javad GNSS as well as having my own survey practice. Our software is geodetic at the core, displaying grid coordinate values and inverses at the user's pleasure. I do believe this will eventually makes its way into our drafting and design software, but not any time soon.

Shawn Billings, RPLS
Owner of Pendulum Surveying in East Texas


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Shawn Billings
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April 15, 2018 3:28 pm  
Posted by: MightyMoe

The major reason I use state plane today is that so many computer programs will talk to it nicely. Yes an LDP will work for me, I've used them for a couple of decades now, but that data doesn't work well for so many other users.

I wouldn't mind a state plane zone that tried to mimic the actual land like an LDP does. That would mean adjusting the scale factor to account for elevations over the zone in question, maybe it isn't possible, but in the areas I work in there would be a number that gets you pretty close. Ignore the mountains, not much work there anyway, so now you have a 3000' range that almost all work is done in, adjust the scale to reflect that number.

Why make the numbers work at 0' on the ellipsoid when the lowest elevation is around 4000' After all it's only numbers and there will be many sites where state plane will be within 10s of ppm. The best you can hope for in the existing State Plane is about 200 ppm and it goes up from there.

When the new SPCS2022 definitions are published, software providers will need to add those zone definitions to their software. If those new zone definitions are LDPs then the software providers will simply be adding smaller LDP zones instead of larger SPCS style zones. Both types will use the same projection types, so no extra overhead there. They should play nicely with the software regardless.

 

The SPCS2022 default designs, which will use the current zones used by SPCS83, will be scaled to the topographic surface instead of the ellipsoid, so there will already be some improvement regarding linear distortion even using the large area zone definitions. LDP designs will be even better regarding linear distortion. 

 

Regarding weighting zone scale factors in mountainous areas, the scale factors would (should) be weighted to provide lower linear distortion in populated areas. This means that rather than a simple average elevation being used, the average will be weighted by population.

Shawn Billings, RPLS
Owner of Pendulum Surveying in East Texas


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Loyal
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April 15, 2018 5:01 pm  

I haven't seen the latest webinar (4/12?) yet, but to be honest, I don't really have strong feelings one way or another.

One thing is for SURE, no matter what the NGS decides to do about State Plane Coordinates, the same folks who can't seem to get their heads around the current system, won't be able to deal with the NEW system either. In fact, it might confuse them even further (assuming the proposed "topographic" changes come to pass).

As always, those who can, WILL, and those who can't, WON'T.

Loyal

 

"Perilous to us all are the devices of an art deeper than we possess ourselves."
Gandalf, The Two Towers


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Mark Mayer
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April 15, 2018 7:13 pm  
Posted by: Shawn Billings
Posted by: MightyMoe

The major reason I use state plane today is that so many computer programs will talk to it nicely....

When the new SPCS2022 definitions are published, software providers will need to add those zone definitions to their software. ....

That's how it is with Oregon's LDP.  StarNet comes loaded with them. Special files are available for C3d and SurveyPro so that it's a one time setup. Seamless. 

 

EDUCATION, n. That which discloses to the wise and disguises from the foolish their lack of understanding.

EXPERIENCE, n. The wisdom that enables us to recognize as an undesirable old acquaintance the folly that we have already embraced.


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Bill93
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April 15, 2018 9:14 pm  

They wouldn't have had to do anything at all except change the name.  They could have just told us to plug 2022 lat-lon into the old NAD83 formulas and call that the new state plane system.  With proper metadata that would work, but people would probably confuse things if the false N and E didn't change..

So the need for a new system is an opportunity to reduce the need to monkey with the lengths (and too often coordinates) in many applications.

Iowa has a 14-zone LDP regional coordinate system.   It would seem to make sense to have a whole-state SPC for GIS work and re-use the existing zones with the needed changes for careful work.

 


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JaRo
 JaRo
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April 15, 2018 9:21 pm  
Posted by: Shawn Billings
Posted by: JaRo

I want two things. 

1) Grid North is still Grid North

2) None of the coordinates go over 9,999,999.99

Both are technically possible, James, but would add a significant additional effort to the design of the LDP (at least regarding Grid North).  I've heard this request before and the reason given was so that coordinates from SPCS83 could be translated without the need for rotation. Is this your reasoning as well?

 

What many of the State-wide LDP designers are doing is giving a grid origin (i.e. False N, False E) value that identifies the particular zone the coordinate belongs to. So if you have 20 zones for a State, the Northing of Zone 1 would be in the 1,000,000's, and the Northing of Zone 13 would be in the 13,000,000's.

Grid North has been Grid North for 91 years. I have been using Grid North for almost every boundary survey I have done for 27 years. and a few before then. I can take a survey I did last year and put it with a survey I did down the road in 1991, then survey the tract in between and expect it to match the bearings of both reasonably well.

My reason for the coordinates being below 10 million is mostly a matter of convenience. I have template files for the Texas Central 4203 and the North Central 4202 zones that I use on TxDot jobs. They have published a surface adjustment factor for each county and I can change that in my template file to get on the same coordinate system they are using. The 0,0 point for the North Central 4202 zone is 300 miles off the coast of Mexico in the Pacific Ocean, 490 miles Southwest of Mexico City. The 0,0 point of the Central 4203 zone is 730 miles south of that and 237 miles North of the Equator. I cannot create a file for the South Central zone because that point is somewhere South of the Equator. I just haven't figured out how to make that work yet. 10 million feet is 1894 miles. I just don't see any reason to measure something and reference it to a random point more than 1894 miles away.

Besides all that, with a coordinate over 10 million I can only key it into my HP41 to two decimal places.  🙂 

James

East Texas, Like a State of it's own, It's a State of Mind.


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Loyal
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April 15, 2018 9:51 pm  
Posted by: JaRo
Posted by: Shawn Billings
Posted by: JaRo

I want two things. 

1) Grid North is still Grid North

2) None of the coordinates go over 9,999,999.99

Both are technically possible, James, but would add a significant additional effort to the design of the LDP (at least regarding Grid North).  I've heard this request before and the reason given was so that coordinates from SPCS83 could be translated without the need for rotation. Is this your reasoning as well?

 

What many of the State-wide LDP designers are doing is giving a grid origin (i.e. False N, False E) value that identifies the particular zone the coordinate belongs to. So if you have 20 zones for a State, the Northing of Zone 1 would be in the 1,000,000's, and the Northing of Zone 13 would be in the 13,000,000's.

Grid North has been Grid North for 91 years. I have been using Grid North for almost every boundary survey I have done for 27 years. and a few before then. I can take a survey I did last year and put it with a survey I did down the road in 1991, then survey the tract in between and expect it to match the bearings of both reasonably well.

My reason for the coordinates being below 10 million is mostly a matter of convenience. I have template files for the Texas Central 4203 and the North Central 4202 zones that I use on TxDot jobs. They have published a surface adjustment factor for each county and I can change that in my template file to get on the same coordinate system they are using. The 0,0 point for the North Central 4202 zone is 300 miles off the coast of Mexico in the Pacific Ocean, 490 miles Southwest of Mexico City. The 0,0 point of the Central 4203 zone is 730 miles south of that and 237 miles North of the Equator. I cannot create a file for the South Central zone because that point is somewhere South of the Equator. I just haven't figured out how to make that work yet. 10 million feet is 1894 miles. I just don't see any reason to measure something and reference it to a random point more than 1894 miles away.

Besides all that, with a coordinate over 10 million I can only key it into my HP41 to two decimal places.  🙂 

James

91 years?

I don't think so, more like 83 or so, but who's counting. Oh, and BTW, there is a slight difference between NAD27 and NAD83 Grid North (depending on the State in question, it can be quite a bit), and even some VERY small variances between Realizations (although not enough to effect most practical applications).

Just say'n.

Loyal

"Perilous to us all are the devices of an art deeper than we possess ourselves."
Gandalf, The Two Towers


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Gene Kooper
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April 15, 2018 10:06 pm  
Posted by: Glenn Borkenhagen
Posted by: Gene Kooper

I do not ever recall seeing this as a design factor in the NAD27 SPC definitions.  Not that I doubt you, but can you provide a reference?

Check NOAA Manual NOS NGS 5 State Plane Coordinate System of 1983 by James E. Stem, a PDF of which is available for download from the NGS web site, specifically the pages numbered 1 and 2 on the bottom.

GB

Thanks, Glenn.

I found this link to NOAA Manual NOS NGS 5 1989-01 rev: 1990-03 State Plane Coordinate System of 1983

Its bibliography cites this USCGS Special Publication:

Special Publication No. 235 1945.0 rev: 1987 The State Coordinate Systems (A Manual for Surveyors)


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Bill93
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April 16, 2018 5:38 am  

Grid north depends on where you are relative to the central meridian of the zone.  If the zones are changed the meridian is likely to be different so your grid north at a given place will change.

There is also the option  in play of offsetting the "central" meridian so the map plane better fits the tilt of the land surface, even if the zone extent does not change.


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JaRo
 JaRo
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April 16, 2018 6:12 am  
Posted by: Loyal
 

91 years?

I don't think so, more like 83 or so, but who's counting. Oh, and BTW, there is a slight difference between NAD27 and NAD83 Grid North (depending on the State in question, it can be quite a bit), and even some VERY small variances between Realizations (although not enough to effect most practical applications).

Just say'n.

Loyal

The difference in Longitude at the water tower downtown BY2762 from NAD27 and the latest listed NAD83 is 0.83982 seconds.

The conversion factor (sinBo) for 27 is .5150588857 and for 83 is .515058882235

The difference between grid north now and 91 years ago is about 1/2 a second.

For the purpose of boundary surveying I stand by my statement, Grid North has been Grid North for 91 years.

East Texas, Like a State of it's own, It's a State of Mind.


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MightyMoe
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April 16, 2018 7:28 am  
Posted by: Mark Mayer
Posted by: Shawn Billings
Posted by: MightyMoe

The major reason I use state plane today is that so many computer programs will talk to it nicely....

When the new SPCS2022 definitions are published, software providers will need to add those zone definitions to their software. ....

That's how it is with Oregon's LDP.  StarNet comes loaded with them. Special files are available for C3d and SurveyPro so that it's a one time setup. Seamless. 

 

As long as C3D, Bentley and all the other CAD/GIS programs come with them preloaded then cool, otherwise I'm not interested in them, too much trouble explaining how to use them and converting my data from them to usable coordinate systems for all the other users who call/email me.

The soil engineer, the subdivision developer, downhole designers, wetland/stream mitigation people,,,,,and on and on, they all use my data, which is cool, but they can't use my LDP's and get their photos and their data bases behind it. I'm not fighting that fight anymore, tired of it.


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MightyMoe
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April 16, 2018 8:06 am  

It's about 2-4 seconds from what I've seen, that is from located 27 monuments, not a calculated number.


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Javad GNSS

Norman Oklahoma
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April 16, 2018 8:13 am  

....The soil engineer, the subdivision developer, downhole designers, wetland/stream mitigation people,,,,,and on and on, they all use my data, which is cool, but they can't use my LDP's and get their photos and their data bases behind it. I'm not fighting that fight anymore, tired of it....

Really, it's better than that. Because the CSF's are so near 1.00 most users -by that I mean the non-surveyor users-  can just treat them as local coordinates and never notice any difference. Or, as I've already said, if they need to use a grid system, as when using RTK, or GIS databases, the "official" zone definition will be pre-loaded.     

I agree that loading custom systems is a collaboration pain in the rear. But LDPs give you almost all of the advantages of the custom zone without the disadvantages.      

 

"Convention is like the shell to the chick, a protection till he is strong enough to break it through." Learned Hand


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Shawn Billings
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April 16, 2018 8:18 am  

It's a good point, James. Thank you for the comment. I mostly work in North Central Zone. They changed the Central Meridian used in SPCS83 from the one used in SPCS27, so it's never been an issue for me. Also, until GPS became prevalent in our area (after 2000) most didn't use any sort of repeatable bearing basis, much less State Plane Grid, so there isn't a huge body of work locally that is based on grid, although that continues to change.

Shawn Billings, RPLS
Owner of Pendulum Surveying in East Texas


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Shawn Billings
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April 16, 2018 8:21 am  
Posted by: MightyMoe
Posted by: Mark Mayer
Posted by: Shawn Billings
Posted by: MightyMoe

The major reason I use state plane today is that so many computer programs will talk to it nicely....

When the new SPCS2022 definitions are published, software providers will need to add those zone definitions to their software. ....

That's how it is with Oregon's LDP.  StarNet comes loaded with them. Special files are available for C3d and SurveyPro so that it's a one time setup. Seamless. 

 

As long as C3D, Bentley and all the other CAD/GIS programs come with them preloaded then cool, otherwise I'm not interested in them, too much trouble explaining how to use them and converting my data from them to usable coordinate systems for all the other users who call/email me.

The soil engineer, the subdivision developer, downhole designers, wetland/stream mitigation people,,,,,and on and on, they all use my data, which is cool, but they can't use my LDP's and get their photos and their data bases behind it. I'm not fighting that fight anymore, tired of it.

Ideally the new LDP for a State would become the State Plane Coordinate System for the State, so of course manufacturers would add these systems to their software. As Mark said, you have all the advantages of a custom coordinate system plus the advantage that SPCS currently has in bein preloaded in our software.

Shawn Billings, RPLS
Owner of Pendulum Surveying in East Texas


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