2018 GPS on BM's - Recover / Observe / Report

[rmaher]

National Surveyors Week is March 18-24, 2018.

Below is an idea for your chapter to do something that will directly benefit you and other surveyors in your area.



2018 GPS on BM's (flyer)

NOAA’s National Geodetic Survey encourages anyone with survey-grade Global Positioning System (GPS) receivers to help perform GPS on Bench Marks (GPS on BMs) to support the development of GEOID18 and transformation tools that will be produced for North American-Pacific Geopotential Datum of 2022 (NAPDGD2022).

GPS on BM data for GEOID18 will be accepted through the end of August 2018.

The nation’s height system, the North American Datum of 1988 (NAVD 88), is founded on historic geodetic leveling surveys that use thousands of bench marks, many of which have not been positioned with GPS. Adding GPS coordinates to these marks allows them to be used in NGS’ modern height reference-surface modeling. GEOID18 will be the last hybrid geoid model that NGS will produce to provide NAVD88 equivalent heights.

Click here for a WEBMAP that shows the bench marks needing occupation in your area.

• Find your local bench mark.
  Collect GPS on your selected bench mark following careful field procedures.
  Complete reconnaissance at your selected mark to ensure its usability, and submit a mark recovery via the online form or DSWorld.
  Collect a 4+ hour GPS data file.
  Use a fixed-height tripod (recommended), and brace the legs with sandbags or chain.
  Verify antenna type, height and plumb.
  Take two photos of the mark, and note any changes to the existing mark description. (Optional: use observer field log with this step.)
  Share your data by uploading to the Online Positioning User Service (OPUS) on the NGS website.

Pretty simple, they're looking for 2 4hr observations. Some of these BM's have already been observed once and they just need a second. If you want to participate, here is a link to the CA ones and if you post here in this thread I'll mark off the site as claimed. If it has 0 prior observations, please note if you'll do both or just 1. Tracking Sheet

[rmaher]

I'm laying a claim on:
TIDAL 2 NP
PID : DX1969
State : CA
County : ORANGE
ObsCnt Requested : 1

[RasterMaster]

Caltrans District 4 is claiming;
1) HT 3504 “941 5020 K Tidal” Marin.
2) HT 0024 “43 A” Alameda
3) Js2282 “D 644” Yolo.

Paul Rogers

[rmaher]

Caltrans District 4 is claiming;
1) HT 3504 “941 5020 K Tidal” Marin.
2) HT 0024 “43 A” Alameda
3) Js2282 “D 644” Yolo.

Paul Rogers

YOLO indeed Paul. Noted and entered into Tracking Sheet

[Jim Frame]

I've been thinking about observing D 644 as well. Paul, can you let me know when you plan to occupy it? I'd hate to block out half a day and then arrive to find Caltrans sitting on it.

[rmaher]

I've been thinking about observing D 644 as well. Paul, can you let me know when you plan to occupy it? I'd hate to block out half a day and then arrive to find Caltrans sitting on it.

Noted, YOLO as well.

[rmaher]

I sent an email with a link to this forum thread to all the CLSA chapters ... looking forward to seeing the volunteers step up to knock this out for our state.

Also, if you're aware of an agency that surveys regionally or statewide, please point me to them (I've already contacted the state geodetic coordinator - works at CADOT about CADOT).

[Jim Frame]

3) Js2282 “D 644” Yolo.

I got out there today after looking at the weather report for the rest of the week. Caltrans can proceed at will.

My understanding is that multiple observations are only required when a mark is going to be used to control the geoid model, and I don't think they'll want to hold D 644 because I suspect that it's been subject to a lot of subsidence. But I figure more is better anyway, so I hope Caltrans observes it as planned.

[rmaher]

3) Js2282 “D 644” Yolo.

I got out there today after looking at the weather report for the rest of the week. Caltrans can proceed at will.

Please share any learning experiences going through the submission process!

[David Kendall]

Caltrans District 4 is claiming;
1) HT 3504 “941 5020 K Tidal” Marin.
2) HT 0024 “43 A” Alameda
3) Js2282 “D 644” Yolo.

Paul Rogers

HT 3504 is a nice spot pack your fishing pole

[SPMPLS]

It is excellent to see this forum being used to coordinate these GPS on BM observations by using the tracking sheet that Rich created. Using a common location to coordinate will help avoid occupation conflicts and maximize efficiency across the state. Although the annual push is to perform the needed occupations during National Surveyors Week, it is important to keep in mind that the effort this year is to collect and submit these data before the end of August 2018 so they can be included in the development of GEOID18. So, if you can't get out, or get everything organized, say at the CLSA chapter level by National Surveyors Week, all is not lost. So keep it up until the end of August, folks.

Regarding observations of leveled bench marks in areas of known subsidence, the NGS is coordinating an effort to specifically address this problem. Dana Caccamise, NGS Pacific SW Regional Geodetic Advisor, is a key member of that team. As the California Geodetic Coordinator, I am also involved. As Jim said, it would be incorrect to constrain the geoid model to the leveled heights for these marks, but there are some large geographic areas of major subsidence in California (up to 3 plus feet in some areas over the past 10 years). Leaving the undulating gravimetric geoid surface unconstrained to NAVD88 across these large areas is not an optimal solution either, although there are many areas of California that have no NAVD88 leveled bench marks to use at all. At the very least, observing bench marks in subsidence areas will allow NGS to analyze the amount of vertical displacement that has taken place, validating that these marks should not be used to develop GEOID18. Other ideas are being discussed to address this issue.

Scott P. Martin, PLS

[Jim Frame]

Please share any learning experiences going through the submission process!

I have only two things to report:

1. The photo upload timed out. I hit by browser's back button, which returned me to the upload page. I hit the Submit button again, and the upload worked on the second try.

2. When I received the draft solution page for review, I noticed that it lists the contributor as jhframe, which is the first part of my submittal email address. I never saw an opportunity to enter my NGS contributor ID (FRAME). I've sent email to the OPUS team to see if I overlooked something.

Otherwise, everything went smoothly.

[Jim Frame]

I'm only a little bit embarrassed to learn that I submitted a 4-hour observation at D 644 almost a year ago. I had completely forgotten about that. The bad news being my pathetic memory, the good news is that the two solutions agree within a millimeter horizontal and 16 mm ortho height. Last time I used a Compact L1/L2 w/GP, this time a Zephyr Geodetic.

[rmaher]

City of Los Angeles claiming these for now and may look into others later:

1. DESIGNATION - 201 86
PID - EW0472
USGS QUAD - SLEEPY VALLEY (1995)

2. DESIGNATION - RV 29
PID - EW4736
USGS QUAD - FILLMORE (1951)

3. DESIGNATION - 23 23.1
PID - AA3189
USGS QUAD - FILLMORE (1951)

4. DESIGNATION - ARROYO SEQUIT J 7 RESET
PID - EW4239
USGS QUAD - TRIUNFO PASS (1994)

Noted and entered into Tracking Sheet

Thank you Robert Nielsen, Cesar Bregaudit, William Knight, Michael Van Egdom, and Bobby Rivera

[PLS7393]

It sure would be nice if the County's and Cities stepped up and assisted on this, but then the majority of agencies (state wide) don't have surveyors associated with CLSA or even visit this site.

Has anyone sent an email to the member of the County Surveyors Association to get the work out?

[gahelmer]

While GPS on BMs is a worthy project that will benefit the local surveying community with an improved hybrid model, I've got to question the entire premise. If additional ellipsoid - orthometric height observations are necessary to deliver the 1 cm geoid model that NGS promises, is it not their responsibility to get those observations? How is it that the federal government is passing off their obligations to local governments and the private sector, and then taking credit, and authority over, the resulting product.

[Jim Frame]

If additional ellipsoid - orthometric height observations are necessary to deliver the 1 cm geoid model that NGS promises, is it not their responsibility to get those observations?

The NGS budget allocation is far too limited to allow it to deliver the level of service its professional staff would like to deliver. Obtaining informal donations-in-kind from stakeholders is the next best thing.

[rmaher]

If additional ellipsoid - orthometric height observations are necessary to deliver the 1 cm geoid model that NGS promises, is it not their responsibility to get those observations?

The NGS budget allocation is far too limited to allow it to deliver the level of service its professional staff would like to deliver. Obtaining informal donations-in-kind from stakeholders is the next best thing.

These are the cards we've been dealt ... in this case the "government" isn't going to fill the gaps and we're uniquely placed as a profession to contribute and enhance the framework that will improve the upcoming geoid and future translations tools.

In that light, I'd like to also say that personally I think Greg Helmer, a humble man, is a great contributor amongst a small group that has benefited the geospatial community of this state greatly through untold volunteer hours and application of his knowledge and experience.

The rest of us slackers can get out there and occupy some benchmarks!

[rmaher]

It sure would be nice if the County's and Cities stepped up and assisted on this, but then the majority of agencies (state wide) don't have surveyors associated with CLSA or even visit this site.

Has anyone sent an email to the member of the County Surveyors Association to get the work out?

In our chapter we have a strong participation by local (and out-of-county) agency surveyors. We try and put forth an agenda and actions centered on the profession and I think that transcends the private/public line, as evident by our membership. Furthermore, when I attend CLSA conferences or Board of Director meetings, I think I see a fair representation from the public sector.

I am curious, because this would be a good target for our state membership drive ... Is that a verified statistic that "the majority of agencies (state wide) don't have surveyors associated with CLSA"?

Both on this thread so far and in several emails by far the most responsive and interested in participating have been those in the public sector. I think they feel this is an area they can assist with time dedicated from public resources perhaps easier than a private surveyor taking time away from making a living. Several representatives of various districts within CDOT and several counties have contacted me. In addition, this topic has started passing through the League of California Survey Organizations I appreciate the idea of CSA, I'll send them an email tomorrow.

Let's put it to a challenge ... private vs. public sector GPS on BM's; I can use the tracking sheet to score. While we're challenging in the interest of the profession; How many are Keith Nofield Land Surveying going to occupy? KDM Meridian is betting you one, go ahead see or raise me :) I'll have to drive out of county to keep up.

Not tomorrow though ... I'll be calling in to the rescheduled Webinar SECTION 8762/8771 ROS TRIGGERS. We certainly appreciate the folk that volunteer their time to pass along their knowledge and experience.

[rmaher]

It is excellent to see this forum being used to coordinate these GPS on BM observations by using the tracking sheet that Rich created. Using a common location to coordinate will help avoid occupation conflicts and maximize efficiency across the state.

Thank you Scott, and thank you for being the NGS State Geodetic Coordinator.

There will be a relevant article issued shortly on this very topic and I will share it here when available.

Meanwhile I'd like to add a couple points.

We're special here in CA ... we have some distinct issues that mean the basic nation-wide request could use some modification. 4 hours is great, but that's very much a minimum. Yes, 5 or 6 hours is actually preferred ... I know, I know ... that's a lot of time occupying a point. I'm just relaying a fact and I know I'll be bringing a good book and a cooler of drinks and snacks when I occupy mine.

Clearly some of these points will be found to be currently not great GPS observation points, or inaccessible, or difficult to occupy. Never fear, Scott and Dana are more than willing to research and provide alternate points in that case ... just let them know here or by email. I'll update the tracking sheet when they let me know of the replacements. I don't have control over the map that is linked in the original post however.

More to come in the near future on these particulars, but I wanted to share that GPS on a BM is like beer ... more is better. So when you get past that 4th hour, press on and give it a little more if you can.

[rmaher]

Doesn't it figure ... if you post stay tuned it is coming soon, it's the very next day.

The article I referred to, link below. Dana Caccamise is the NGS Regional Advisor (based in La Jolla at the CSRC on UCSD)

GEOID18: Make Your Mark and Improve Your Heights

[gahelmer]

If additional ellipsoid - orthometric height observations are necessary to deliver the 1 cm geoid model that NGS promises, is it not their responsibility to get those observations?

The NGS budget allocation is far too limited to allow it to deliver the level of service its professional staff would like to deliver.

Limited budget is of course true. And I don't mean to discourage helping ourselves. In the last year, NGS did seem to somehow find the money to perform gravity surveys in Guam and Marianas, sent several people to Paris and Finland for conferences, ran a control survey and flew imagery for Chesapeake Bay, and positioned a telescope on the Virgin Islands.

[Jim Frame]

Limited budget is of course true.

When I posted my "limited budget" response I did so without looking carefully at the ID of the poster to whom I was responding -- I figured it was someone not familiar with NGS. My mistake!

[Jim Frame]

My JS2282 session is on the web now: https://geodesy.noaa.gov/OPUS/getDatash ... PID=JS2282

[rmaher]

Came across this HOW TO document for those participating. Nice to have it distilled down into a cheat sheet for you and/or your crews!

I continue to get emails and I have been updating the TRACKING SHEET.