I want two things.?ÿ
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).?ÿ 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?
?ÿ
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.?ÿ ??ÿ
James
I want two things.?ÿ
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).?ÿ 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?
?ÿ
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.?ÿ ??ÿ
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
I do not ever recall seeing this as a design factor in the NAD27 SPC definitions.?ÿ 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)
Grid north depends on where you are relative to the central meridian of the zone.?ÿ 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?ÿ 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.
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.
The major reason I use state plane today?ÿis 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.?ÿ StarNet comes loaded with them. Special files are available for C3d and SurveyPro so that it's a one time setup. Seamless.?ÿ
?ÿ
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.
It's about 2-4 seconds from what I've seen, that is from located 27 monuments, not a calculated number.
....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-?ÿ 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.?ÿ ?ÿ ?ÿ
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.?ÿ ?ÿ ?ÿ?ÿ
?ÿ
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.
The major reason I use state plane today?ÿis 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.?ÿ StarNet comes loaded with them. Special files are available for C3d and SurveyPro so that it's a one time setup. Seamless.?ÿ
?ÿ
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.
Actually, I believe Mark is saying that special files are available, that isn't good enough for me. I have way too many users to track down, often I don't even know who is using data. As long as it's seemless then I'm good with it. If I have to convert or add to other people's programs, then I'm not good with it. No doubt the new state plane systems will be imputed to each new version of autocad, trimble, ect.
That will be inevitable. Regardless of whether a State adopts a Low Distortion Projection zone approach or a large area projection approach, the parameters will be different from what is currently used in SPCS83 which means any users working with SPCS2022 will need to update the projection definitions in their software, whether that be a patch from the developer or manual entry of parameters in a coordinate system editor in the software. No way around that.
Bill
Iowa has had a statewide CS for GIS for many years. UTM 15.
Also Iowa will likely change the Eastings in the 14 zones by 10 million in 2022 to avoid small differences of a couple of ft on a mark
That will be inevitable. Regardless of whether a State adopts a Low Distortion Projection zone approach or a large area projection approach, the parameters will be different from what is currently used in SPCS83 which means any users working with SPCS2022 will need to update the projection definitions in their software, whether that be a patch from the developer or manual entry of parameters in a coordinate system editor in the software. No way around that.
I agree Shawn.
Inputting Projection Parameters into a Data Collector, CAD, Office (whatever), software shouldn't take more than a minute or two per Projection/Zone/whatever. The "bookkeeping" involved with keeping Datums, Realizations, etc., straight, is another question altogether, and a matter of metadata in general.
Regardless of how "SPC22" is defined (realized), some folks will have problems implementing the new paradigm into their work flow, AND correlating the "new" with the "old." ?ÿNothing new there, we had the same problems between NAD27 and NAD83(86), as well as keeping up with later realizations of NAD83.
Looking forward to watching the spatial paradigm circus as it unfolds in a couple of years.
Loyal?ÿ?ÿ
Bill
Iowa has had a statewide CS for GIS for many years. UTM 15.
Also Iowa will likely change the Eastings in the 14 zones by 10 million in 2022 to avoid small differences of a couple of ft on a mark
Ditto for several other Western States.
Utah uses UTM Zone 12, Nevada uses UTM Zone 11. Wyoming actually has a State-wide Lambert, but I don't know anybody who actually uses it.
In many ways, I have come to embrace the Montana decision to go with a "high distortion" state-wide SPC projection. It gets everything on the "same page" for the GIS folks, still works "okay" for the surveyors who understand it, and is obviously a POOR choice for retracing cadastral surveys.
As others have stated before, I would be perfectly happy with using a BLM/PLSS "True Bearing/Surface Distance" for "LAND" Surveying (at least here in the Mountain West where virtually ALL land titles originate in said system). Of course (like Shawn indicated), very few software packages support such a system.
Loyal
Layered Zones:
The new SPCS2022 will allow for a layered system of zones. One would be Statewide and the other "sub-zones" would be either the slightly modified existing State Plane Zones or new LDP zones. This will hopefully make it easier for States to adopt the LDPs as stakeholders who want a Statewide system can have it as well.
Layered Zones:
The new SPCS2022 will allow for a layered system of zones. One would be Statewide and the other "sub-zones" would be either the slightly modified existing State Plane Zones or new LDP zones. This will hopefully make it easier for States to adopt the LDPs as stakeholders who want a Statewide system can have it as well.
Roger that Shawn, that is one of the things brought up in the March Webinar that I really liked!
The vast majority of my work will continue to be done in the boondocks, so it's unlikely that a [relatively] large LDP will happen to be the "best fit" for one of my projects, but I don't worry about such things.
As ALWAYS, metadata?ÿis the spatial "footsteps" that we can leave for the next guy/gal to follow.
Loyal?ÿ
Iowa has had a statewide CS for GIS for many years. UTM 15.
A few years ago I saw some county GIS systems displaying SPC.?ÿ Recently, I haven't noticed any coordinate display available on most of them I've used.
There are numerous trades that use our data and have no clue what a geographic coordinate is. We also have millions of owner clients who have zero use for a lat long height.
Relating geographic, grid and ground is becoming second nature for most of us. Expecting our client base to make that journey is unreasonable.
Actually, I believe Mark is saying that special files are available, that isn't good enough for me..
That's true, I am. But once 20, 30, or more states have agency defined LDPs I'm sure that they will come installed.?ÿ
