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Shelby H. Griggs PLS
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March 8, 2018 9:28 pm  

Did anyone attend the NGS webinar on March 8th? I signed up, ended up being out of office and couldn't get it to load on my phone, so hopefully it was recorded!

SHG

PLS CA, ID, NV, OR, WA
Commercial Vehicle Driver


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Rick Taylor
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March 9, 2018 6:21 am  

I attended. It was the best one hour treatment of the subject I have seen. Michael Dennis was the presenter, and yes it was recorded, will be available on the NGS website. This was basically Part 1; there's also a followup scheduled for April 12. Should be a good one.


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SPMPLS
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March 9, 2018 6:39 am  

This document was posted yesterday just in time for Michael's presentation. It was outstanding and well worth watching the recording when available.

https://geodesy.noaa.gov/library/pdfs/NOAA_SP_NOS_NGS_0013_v01_2018-03-06.pdf

Best to watch it before the April Part 2 webinar, where he will get into more details.


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Shelby H. Griggs PLS
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March 9, 2018 9:38 am  

Thanks guys, I know Michael and I figured it would be excellent, look forward to the recording.

PLS CA, ID, NV, OR, WA
Commercial Vehicle Driver


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mkennedy
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March 9, 2018 1:33 pm  

Thank you for posting the link to the new SPCS document. I had to miss the webinar due to a conference but plan to watch it as soon as it's available.

 

Melita

Melita Kennedy
Coordinate reference system and transformation specialist at Esri


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SPMPLS
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March 15, 2018 8:25 am  

The recording of the webinar is now available:

https://geodesy.noaa.gov/web/science_edu/webinar_series/2018-webinars.shtml


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Shelby H. Griggs PLS
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March 15, 2018 9:56 pm  
Posted by: SPMPLS

The recording of the webinar is now available:

https://geodesy.noaa.gov/web/science_edu/webinar_series/2018-webinars.shtml

Thanks, yes I recieved an e-mail from NGS too.

PLS CA, ID, NV, OR, WA
Commercial Vehicle Driver


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Loyal
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March 18, 2018 10:21 am  

Question:

How many of you folks have watched the above (excellent) Webinar so far?

Okay, one more question;

What do you think of the proposal for "projecting" the 2022 SPC coordinates to the "topographical surface," as opposed to the current system of using the ellipsoidal surface?

Yeah...I know, that's somewhat of an oversimplification, but if you watched the Webinar, you know what I mean.

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 Silver
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March 18, 2018 2:54 pm  

Michael Dennis is  a Rock Star. He can make what would be a boring webinar a real interesting hour.

Not only did I greatly enjoy the March 8th reel, but looking forward to next installment and partially through the new document.

Topo surface will be way to roll in east. I don't have a clue how it will work here, unless the zones are really-really-really-really-really small.

Maybe we can have a unique zone for each section?


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Gene Kooper
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March 18, 2018 3:27 pm  
Posted by: Loyal

Question:

How many of you folks have watched the above (excellent) Webinar so far?

Okay, one more question;

What do you think of the proposal for "projecting" the 2022 SPC coordinates to the "topographical surface," as opposed to the current system of using the ellipsoidal surface?

Yeah...I know, that's somewhat of an oversimplification, but if you watched the Webinar, you know what I mean.

Loyal

I haven't had time to watch, but will.

To answer your question, that is a VERY bad idea.  SPCs are SPCs!  Leave them alone.  If the NGS wants to adopt a new projection (with a new name) that projects the coordinates to the "topographic surface" more power to them; just don't call it SPCs.  We will work with SPCs for many years to come.  While SPCs are not foolproof, changing the SPC projections for the new datum would be a disaster because fools are so ingenious!

My $0.02 opinion, nothing more.


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Loyal
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March 18, 2018 3:47 pm  

Check this out...

https://en.wikipedia.org/wiki/List_of_U.S._states_and_territories_by_elevation

and do the math.

There are 29 states & the District of Columbia that have LESS relief than Salt Lake City (5200 ft. within the City Limits)

Like Mark says, there are certainly States [back East] where this might work good (even great), but NOT out here in the West. I agree with Gene, it will be a recipe for disaster, there are too many folks who can't even deal with the State Plane System as it is!

Loyal 

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


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MathTeacher
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March 18, 2018 6:12 pm  

It's interesting that Mr. Dennis chose North Carolina as one of his example states. Instead of defining the NC Lambert projection by two standard parallels, he defined it by fixing the central parallel and the scale factor on the central parallel. That's a concept that we discussed here a while back, noting that the same Lambert projection can be defined in either of the two ways.

We're not like the Rocky Mountain states,but we do vary in elevation from below sea level to more than 6,000 feet, so we do have distortion problems at the extreme ends of the state. The projection that Mr. Dennis described is only slightly different from the 83 version, but it will change coordinate values. He didn't mention the central meridian, so I assume that it stays at 79 degrees. It was all hypothetical, of course, but it does make an old math guy think.

I haven't looked at the math, but I suspect that there may be a fairly straight-forward transformation between the new and the old projections. Perhaps he will address that in the next webinar. In case he doesn't, I need to work on that now, 'cause I may not be around in 2022.

 

As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality. Albert Einstein


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MathTeacher
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March 18, 2018 6:14 pm  

It's interesting that Mr. Dennis (or is it Dr. Dennis now?) chose North Carolina as one of his example states. Instead of defining the NC Lambert projection by two standard parallels, he defined it by fixing the central parallel and the scale factor on the central parallel. That's a concept that we discussed here a while back, noting that the same Lambert projection can be defined in either of the two ways.

We're not like the Rocky Mountain states,but we do vary in elevation from below sea level to more than 6,000 feet, so we do have distortion problems at the extreme ends of the state. The projection that he described is only slightly different from the 83 version, but it will change coordinate values. He didn't mention the central meridian, so I assume that it stays at 79 degrees. It was all hypothetical, of course, but it does make an old math guy think.

I haven't looked at the math, but I suspect that there may be a fairly straight-forward transformation between the new and the old projections. Perhaps he will address that in the next webinar. In case he doesn't, I need to work on that now, 'cause I may not be around in 2022.

 

As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality. Albert Einstein


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Norman Oklahoma
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March 19, 2018 9:17 am  
Posted by: MathTeacher

It's interesting that Mr. Dennis (or is it Dr. Dennis now?) chose North Carolina as one of his example states....

 

North Carolina was the state that initiated the development of the whole State Plane system back in the '30s.  So it's appropriate to go back to that point when discussing new concepts.   

"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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Bill93
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March 19, 2018 12:27 pm  

I watched the recording today.

I don't see their proposed methods as creating any new problems.  It is still an SPC just like the old ones except for the scale factor (and trivial changes in origin, etc.).  The talk about topographic surface means that they pick a scale factor that better fits the ground elevations in the zone instead of a scale factor that fits the ellipsoid.  Knowing that factor, you can still correct for differences in elevation just like you do now to bring distances to ground when the distortion is more than you can tolerate. 

You can still make modifrickinfied ground coordinates and Loyal and I will harp at you to knock off the millions and hundred thousands so it is obvious they aren't pure SPC.

This doesn't fix the whole problem for zones with a lot of elevation relief but it doesn't hurt them either, and it does help flatter areas.

I'm hoping that their "layer" stuff means that Iowa gets a whole-state SPC and 14 sub-zones matching up with the present Iowa Regional Coordinate System, and that NGS supports this by putting both sets of coordinates in the data sheets and OPUS reports.


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