California Surveyors Forums

Colleagues:
It is my pleasure to announce that NOAA's NGS published the geoid model, GEOID09, on Sept 22, 2009. As I had been telling many, I was very confident (but not absolutely sure!) that it would be out this week or by the end of the month. So there!

Information can be found here:
http://www.ngs.noaa.gov/GEOID/GEOID09/
Software: http://www.ngs.noaa.gov/PC_PROD/GEOID09/
If you get to our Geoid pages some other way, please make sure you don't accidentally choose to download the USCC2009 or GEOID09BETA models.

In California, there were 833 bench marks with GPS data (ellipsoid heights) considered; 747 were included (exclusions have a red background). Attached is a pdf for just California; the first 18 pages are the left side of a spreadsheet; the next 18 are the right side. (Spreadsheets are not an allowable attachment in this forum.)

To check on the value of GEOID09 at a geographic location of your interest, you can use the below URL (until the specific Toolkit link is made active on our website, first choice under Tools):
http://www.ngs.noaa.gov/cgi-bin/GEOID_S ... rompt1.prl
To compare with GEOID03 (just superceded) values, the link is:
http://www.ngs.noaa.gov/cgi-bin/GEOID_S ... rompt1.prl

It is anticipated that OPUS will soon start using the new geoid, so look carefully at your results. I heard a rumor that both might be used for awhile, but that is speculation.

Please distribute this widely to, or otherwise inform, other colleagues. A notice has already been sent to the email-keepers for NCGPSUG and SCGPSUG. As always, your feedback is of great interest to NGS.
Thank you,
Marti

Hi Marti!

I can't seem to convert the Geoid 09 bin files to Star*Net *.ght file extension using StarGeoid.

Any one else having this problem..... or is it just me? ;.)

Thanks Marti!

I can't do it either. I was going to email Ron, but maybe it's the NGS site???

Ron knows about it. I think that NGS changed the format of the binary code for the new geoid. My guess is that Trimble will have the same problem too and we won't be able to use the new model for a while, at least until all the software is updated.

Hi:
I don't believe that we changed the format of the files; I can find nothing to that effect in the documentation. It is possible that various commercial adjustment software manufacturers would have to modify their software to allow/incorporate a different geoid model.
Did you download both software programs? INTG and XNTG (data)?
Did you follow the directions given in the readme file?
http://www.ngs.noaa.gov/GEOID/GEOID09/g2009rme.txt
I had a typo in my previous post; it should have been USGG2009 (not 'CC'), which stands for Gravimetric Geoid.
Cheers,
Marti

I didn't have a problem converting the *.bin files using StarGeoid, once I had run them through XNTG as explained on the download page. NGS has used big-endian (UNIX-style) formatting for its geoid height files as long as I've been aware. The files need to be converted to little-endian (Windows-style) formatting in order to work correctly with most Windows software. It's a nuisance, but not something that has to be done very often.

.

I don't remember having to do it for Geoid03 grids?

Thanks Jim!

I've been informed that Trimble now has a file on their website for TSCE (Survey Controller) to utilize the new geoid.

http://www.trimble.com/support_trl.asp? ... tion-66364

I was able to post the spreadsheet (xls) in my directory on the NGS ftp site.
ftp://ftp.ngs.noaa.gov/dist/marti/
Also there is a short txt file that has explanations of the codes that are NOT explained in the readme file on the GEOID09 webpage (which pertains to an ASCii file, not the spreadsheet, but which can be figured out.)

Marti,

Thanks for your efforts to get most of the available Height Modernization benchmarks in California included in the new model. Without you looking after the Geodetic interests in California, we would not ended up with the best Geoid model from the available information.

Thanks!

Ron Sawyer (Starplus) and I chatted this morning about the format issue. You DO have to convert the unix friendly format into PC-friendly. I re-read the info on the GEOID03 page, and found this:
Due to numerous requests, the binary formats of the eight data files have now been switched to the native format of Intel based PCs (little-endian).
So Brian C. was right, seemingly, that when he worked with GEOID03, they had already been switched to PC-format.

Moments ago, I sent a request to have that done again for GEOID09 so that thousands of people (ok, maybe hundreds) across the country don't all have to do that. Most people who want to use GEOID09 are on PCs, and I suspect most people who are interested in USGG09 are on unix machines. Hopefully, my request will be granted, and new files will be posted that don't have to be converted using XNTG.

It has come to my attention this morning that the Trimble ggf file used USGG09 instead of GEOID09; they have been notified (yesterday). I have also asked that the GEOID09 files be posted at the top of our page, ABOVE the USGG files since I suspect more people would be looking for GEOID09 than USGG.
Trimble's link is this:
http://www.trimble.com/geomaticsoffice_ ... tion-66364
I hope they would post a comment when they put the corrected ggf there since the filename might well be the same. I'll make a post when I find out that they have corrected the problem.

A workaround was posted on the AZPLS page (an AZ surveyor discovered the problem), which I paste here:

....include Tom’s work
around using the Trimble Grid Factory.


The workaround is to use the NGS geoid files
http://www.ngs.noaa.gov/GEOID/GEOID09
<http://www.ngs.noaa.gov/GEOID/GEOID09> and then use the Trimble Grid Factory
(in TGO utilities) to bring in the correct GEOID model.

Once TGF is running

File ->Import Grids

Use Geoid 99 Files (*.bin) Template

select the geoid *.bin file downloaded from NGS

Give it a description if you'd like



Now correct your geoid definition in Coordinate System Manager

1. My (and Ron Sawyer's) request to have the GEOID09 files provided in PC-compatible format as a default was agreed to. As of this moment, the change hasn't been made yet but check (read!) the page carefully to see whether you have to use XNTG to convert (to a PC-friendly format) or not.
2. Again, at my suggestion, on the main GEOID page, GEOID09 files have been moved to above USGG2009 to try to avoid having people 'grab' the 'wrong' one. There is no note on Trimble's support page to indicate whether or not that is the correct (GEOID09 and not USGG2009) ggf file; if it's not correct, I think they should remove it. All I can say is "Trimble customers, be forewarned" (see earlier post), and perhaps communicate with your support staff to have their webpage make clear whether/when the correct one has been posted.
3. Advisors have also asked for a graphical (illustrated) comparison between the new and old geoid models for the country; that product/link (Comparison of the latest models...) is under construction.
4. Because we tested the draft Datasheet-generating script today, and it's nearly correct, I expect that in the very near future, Datasheets will begin to show the GEOID09 value and model name on them. If you, for some reason, want to preserve the GEOID03 value on the Datasheet for some particular station in our database, I advise you to retrieve it (can be saved as a digital file by choosing 'File, Save As, ...datatype .txt') very soon.
5. Note that just because the Datasheet shows the current published GEOID model name and value, does NOT NOT NOT mean that the orthometric height that is published was determined with that value. We do NOT arrive at the ortho height by arithmetic means, by simply subtracting the (negative) geoid height from the ellipsoid height. It is a least-squares adjustment process, which is why the ortho height rarely, if ever, is the strict sum of those two values. I have argued, not yet successfully, that we should show only the geoid model and height that was USED in the adjustment, NOT the current geoid information which may or may not have been the one used to determine that orthometric height.
6. To determine a geoid height at a latitude/longitude location of your interest, you may use the Toolkit options for GEOIDXX, found here:
http://www.ngs.noaa.gov/TOOLS/
We have 09,06 (pertains only to Alaska), 03, and 99 available.
7. In the compressed ASCII grids listing, Grid #6 (east of California's Grid #5)is now correctly labeled. Thanks to Dan Gilleland's (SCVWD) sharp eyes for catching that error.
8. There is still space available for the free "GPS-Derived Heights" webinars being held from 10-1 each day on Tues and Wed, 10/6 and 10/7. Read the instructions and register online:
http://www.ngs.noaa.gov/corbin/calendar.shtml

I noticed today that Trimble has posted (on 9/30) the corrected ggf file.
http://www.trimble.com/geomaticsoffice_ ... tion-66364

Hi:
I've just been informed that the PC-friendly (little endian) format is now available on the www.ngs.noaa.gov website.
http://www.ngs.noaa.gov/PC_PROD/GEOID09/
Scroll down to the Data paragraph.
The first set is for PC users.

If you have any problems with access, do not hesitate to send your question or comments to the Webmaster, whose information is available at the bottom of that page.

As of this morning, GEOID09 model and values are now shown on NGSIDB datasheets. Please remember that the published orthometric height is not determined by merely combining the ellipsoid height and geoid height; it is the product of a least squares adjustment of the project network.
Additionally, remember that the placement of the geoid height/model on the Datasheet is NOT indicative, unfortunately, that that is what was used in the adjustment.

Has anyone successfully created a .ght file for Geoid09 ?

One of my guys ran thru the translation a month ago Matt. We have been using it seamlessly since then.
Call me if you need some help.

Same here. I have a GHT for California (not sure if I covered the whole state or not) that's about 9MB. I can post it for download if you'd like; just let me know.

If you try it again it should run smoothly since they "fixed" it so it works like it did with GEOID03.