I was assisting a now solo NJ surveyor on topo for a riverside project. The nearest benchmark to the site is in Portland, PA on the West abutment of the last former covered bridge across the Delaware. I recall crossing this bridge in the early 50's when my brothers went to Scout Camp. The bridge was swept away by the Hurricane Diane flood in 1955, and the piers now support a steel pedestrian bridge. We leveled across the bridge to Columbia, NJ and North to the site, personally I would have GPSed it, but "not my job".
The benchmark designation is "L 362" but it is "L 362 Reset", (KV2878).
The data sheet only lists, SPC PA S coordinates in meters. Our NJ site is pretty much due North of the benc mark. In the pasts data sheets like this would have had, SPC PA S and N as well as SPC NJ coordinates, feet and meters. Within site of the benchmark is the Delaware Water Gap and Monroe County which is SPC PA N and a decent part of New Jersey is NW from it. The FEMA panel is marked in SPC NJ meters but is referenced in SPC NJ feet, so an overlay requires some math from the bench.
Is this going to be typical of the future, with the lack of appropriate information?
The lack of information bothers me, while this surveyor was really bummed out for other reasons. The FEMA panel cost $2.50 to his account and over $250 worth of time as his computer kept getting kicked to the curb by the FEMA site.
Without pulling the FEMA .png file into a .dwg what is your preferred method of plotting it to scale?
I was personally bummed out that we have yet to see an Eagle. A few years ago I surveyed directly across the river from this site and every day a 3 PM an eagle would glide North on the heat waves coming off of US 611. He may still be doing that but he actually flew below the treetops so may be obscured.
BTW the area to be developed sits 5'+ above the 1% flood elevation so that is not a problem.
Paul in PA
And how did the disk check out with other bench marks?
The KV2878 data sheet says that it was reset in 2002, but the values are for the original location, since you didn't find a data sheet designated L362 RESET. An older copy of the data sheet has the same elevation.
Did you get new data from PA DOT?
The history of recoveries on the GC site should be perused, comparing the pictures taken in 2003 and 2007, which clearly show two different disks.
I share your pain about the lack of data, but, not seeing an eagle, that is almost too much to bear.:-)
Howdy,
Perhaps I am missing something. You complain that the site shows only metric State Plane coordinates. Given that the position source is "SCALED" with a +/- 180 meters accuracy what use other than rough plotting are the coordinates?
Also IF this is NOT the station but a RESET the coordinates do not apply to it. No datasheet is available for the reset. The datasheet for the monument does not indicate it was destroyed.
I suggest contacting NGS HQ for information about the reset. The NGS relies on its partners to perform resets. Frequently the work is never completed nor forwarded to NGS for processing. There is a nice document on the NGS site discussing reset procedures.
Cheers,
DMM
More lack of understanding about SPC's!
Did not check it to other benchmarks and the only real choice would be to GPS the project and the benchmark.
The data sheet indicates the original mark as "L 362 1978". The last line of the datasheet shows "L 362 RESET 2002" in Southeast Abutment. That is different from the original location.
Today in comparing the resulting contours with the FIRM floodlines at the base flood elevation it may have a significantly different elevation, 5'-7'.
More research is required.
Thanks for the help, though that was not my original goal.
As to my question, I can eyeball a quad sheet location within 1 second so I have no idea why such a large disclaimer.
Is the NGS getting sloppy with the data?
Paul in PA
Paul
"As to my question, I can eyeball a quad sheet location within 1 second so I have no idea why such a large disclaimer.
Is the NGS getting sloppy with the data?"
You're kidding right?
The NGS has NO CONTROL over the “plot” on the USGS Quad (or are you one of those people you think that the USGS, USC&GS, NGS are the SAME folks?).
+/- a couple of hundred feet is a reasonable estimate of the position of a Bench Mark that was plotted by the USGS via UNKNOWN means. Maybe “direct approximate,” “indirect approximate,” MAYBE (but not likely) actually targeted OR surveyed.
Geez...
Loyal
Howdy again,
In the event there is confusion on the matter, a RESET is not set to the original monument's height. A reset is set nearby the original monument which is expected to be destroyed. A lesser set of requirements are associated with determining the height. The manual by Curt Smith of NGS on their site describes what is involved.
The fact that there is reference to a RESET monument without an associated data sheet means that for some reason the RESET data was not processed by NGS. It appears this disk is an "orphan." It was the case that some persons provided a disk by NGS to do a reset did not complete the work.
As for the very conservative estimate of scaling accuracy, in the early 1980's field crews were given the task of using BM descriptions to plot the BMs on USGS quads and scaling the plotted locations. Following some of the old descriptions was challenging. The intent was to get you close enough to be able to use the local ties in the text of the description. Adding hand-held GPS positions to the descriptions is supported in the NGS mark recovery tool.
Cheers,
DMM
