holograph
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Posts posted by holograph
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It will be interesting to see the effect on nearby CORS stations.
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Here are a few of the benchmarks that I have logged to the NGS.
GT0402, GT0415, GT0426, GT1219 and Gt1183. These were all posted in May of this year. I have posted 322 benchmarks to the Geocaching.com site but only in the last few months started posting to the NGS.
None of my statistics show up on the NGS stat page....do you know why?
Yes, the initials "TG" had already been used by bblhed, so the recoveries were being credited to that user. I've modified the tables so that any "TG" recoveries in California get credited to you, and the stats page has been updated.
Since the only identifying information on the NGS datasheets is the initials, I keep a cross reference of initials to geocacher ID. It is not feasible to try to figure out who reported each specific PID, so if a set of initials has been previously identified, all recoveries with those initials are counted under the previously identified ID. For three-letter initials, the assumption is relatively safe. For two-letter initials, it is unsafe, so recently I added a cross reference table which can be used to identify initials within state and county. Unfortunately, bblhed had begun using the "TG" initials in 2004, before I had the new tables in place, so all "TG" recoveries were credited to bblhed.
Now that I've added "TG" to the state/county lookup table, all California recoveries under "TG" will be credited to tom&si. Any "TG" recoveries outside California or Connecticut will be flagged and I will have to do extra work to figure out who should be credited.
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I started logging my benchmark finds to the NGS in April and none of mine have shown up yet!
It takes time for the NGS to update the datasheets. What are some of the PIDs you logged?
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I see that the captions for the maps are now consistent. On the "recent recoveries" map, the seven counties in northwest Ohio show new recoveries through May 31. On the "total recoveries" map, though, the same seven counties show no recoveries through May 31. Which of the two maps is displaying the correct information?
They are all correct, and have been since last June. Very likely you need to clear your browser cache. When I looked just now to check, the thumbnail and full image appeared correctly, but the zoomed-in version didn't appear correctly until I cleared the browser cache. It could be that Adobe Flash has a more aggressive caching policy than the browser has for regular images.
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I guess that the NGS has a somewhat unpredictable update schedule.
I have a question about the maps, which I always look forward to. The top map is captioned "Total GEOCAC Recoveries as of May 1, 2010." The bottom map is captioned "Recent GEOCAC Recoveries from May 1, 2010 to May 31, 2010. Is there a way to have the top map include the recent recoveries shown on the bottom map?
Of course, we all appreciate your endeavors when it comes to updating all of the county maps and numbers. We're all looking forward to the next NGS update!
The maps are consistent. Likely I made a mistake in updating the captions. They both contain data through the end of May.
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Not sure when it occured, but I see the AK data has been broken down to match the boroughs. Thanks to holograph for posting the new data files.
There have been a mixture of old and new datasheets, some have the correct boroughs, some don't. When I collect the datasheets, I assign the old ones to boroughs based on their geographic locations and the boundaries from the Census Bureau's Tiger/Line dataset.
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There were no NGS datasheet updates containing new GEOCAC recovery reports. We'll try again in August.
The June Geocaching.com statistics are available on the statistics page.
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Bullionhunter wrote a nice article on the benchmark wiki: The Adirondack Survey
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Well its not the benchmark I am guessing. I followed the original coordinates and found in the center of the road 11-13 feet from GZ an impression in the road from a round disk like object. Which has to be the benchmark.
The monel rivets are not disks. A number of rivets were set in the general neighborhood of Blairstown by the New Jersey Geological Survey (NJGS), and you can see what they look like in the logs for them: LY0744, LY0743, LY0738, KV1410.
Quite a few other rivets have been destroyed by time and weathering, and they haven't been replaced or reset.
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My best estimate of the Musselshell Ferry is at 472730.0 1075234.0, 0.1 south of SQ0364 on the county line between Garfield and Phillips (historic river channel is the line). A road comes down to the reservoir shoreline 0.61 mi south of this point.
I stitched quads to reproduce your map, and measured along the various roads. Based on the notes for SQ0580 and SQ0435, it's clear that Legg was east of Dry Lake, somewhere under water now. Also, I see now that SQ0364 was 400 feet northeast of the ferry landing, which virtually pinpoints that location.
The odometer readings in the various descriptions seem to be approximate, since they only roughly match the distances as calculated in a GIS program.
After all that, it still doesn't shed much light on the problem with SQ0363, since the odometer reading in its description simply won't get you anywhere near its elevation or water.
Click the thumbnail below for the full reproduction of your map, with annotations.
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If it's any help, the Musselshell Ferry may have been near Fort Musselshell, which was located at N 47.4555534 W 107.9145576, according to the GNIS database. That location is underwater, southwest of the stations, according the the USGS quads. The Musselshell River is also nearby, so possibly the ferry just crossed that river, without any particular relation to the fort, although a crossing near the fort would seem to be useful.
Legg was located at N 47.5930539 W 107.8995583. Wilder was at N 47.6144387 W 108.4520823.
On the USGS quads, there appear to be a number of roads that might be the Wilder-Legg road, and the ones that Kayakbird chose do seem to be good candidates for the road from the ferry to the Wilder-Legg road.
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The May statistics are available on the statistics page. The maps and counts by county have been updated also.
There were 1641 datasheets updated with GEOCAC recovery logs. The most recent recovery added to the datasheets was dated May 27.
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The April statistics are available on the statistics page.
There were no new recovery reports published in the past month, so none of the NGS statistics changed.
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Here are some of the things I am curious about:
RD1645 RTE WILSON R STA 1843+19.6 381.146 METERS 24836
...ON SLOPE BETWEEN WILSON RIVER HIGHWAY AND CONSOLIDATED
'TIMBER COMPANY LOGGING RAILROAD..
.. WALK E ALONG TRACK ABOUT 0.5 MILE TO NE END OF LONG TRESTLE, THEN GO NORTHWARD ABOUT 600 FEET TO STATION.
Also the topo shown by holograph isn't matching the road unless the road is half in the shadow. Shifting it to match the road looks to me like it puts it about on the HH2 coordinate plotted.
- jlw
My experience has been that topos have varying degrees of accuracy for different features. Also, nothing says that the photo's coordinates are the ground truth. The photo orthorectification process distorts pixels based on elevation, so it is only as good as the elevation model.
Here is a larger clip. Notice how well the topo and the photo are aligned in the upper left corner. For instance, the field boundary matches the boundary line on the topo, and the road through the field is exactly aligned with the topo. It's harder to see, but the line of the creek seems to align well, as well as the fork in the plantation road at the upper right. In fact, the only feature that seems to be misaliged is the road through the middle of the figure.
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For what it's worth, here is a NAD83 composite of the USGS Topo map, an aerial photo, and the plotted coordinates of the datasheet and the handheld coordinates. The Topo map was converted from NAD27 to NAD83, the photo was already georeferenced to NAD83, and the stations were plotted in NAD83.
It looks like the USGS had some different coordinates for Wilson than those published in the NGS datasheet.
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The 86-foot difference could just be a case of two errors adding: your GPS coords could be affected by the terrain and trees, and the datasheet coordinates are only third order, so they could also be off by several meters, too. More likely the GPS coords are the main culprit, because from your photos, it doesn't look like a good location for GPS.
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Some of you might also be interested in "Boundaries of the United States and Territories" by Henry Gannet (US Geological Survey), 1900. (Google Books link)
Gannet collected information about the treaties, Acts of Congress, etc. that defined the state boundaries. It may not be as entertaining as the other book, but it is packed with interesting information.
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So now, what is the correct term for the height of a bench mark, Altitude or Elevation?
Both altitude and elevation are somewhat informal terms. If you look at the NGS datasheets, the datasheet uses "ellipsiodal height", "orthometric height", "dynamic height", and other terms that have well-defined technical definitions.
When Geocaching.com extracted the datasheet data, they may have chosen to use the term "altitude" as the term most familiar to their users.
Altitude does seem to be used more often for aviation, and elevation for geography, but there are numerous exceptions. For instance, astronomy software often asks for the observer's altitude when computing ephemerides.
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Benchmark Recovery pays off.
I have a NGS Benchmark DataSheet in hand, I remember it being there as a kid.
PID search on GS says "not found", but it has been destroyed (removed for new construction usage).
At 13:30 on July 28, 1987 a series of 16 color photos were taken of the toppling of the South Water Tank in town. I have a cell phone camera picture of the framed sequence. I believe the photographer was the town mayor at the time.
The tanks removal was part of a land clearing deal that resulted in the construction of the town mall.
The question now is, with the documentation in hand, how do I go about logging the Recovery and detailing its destruction?
Finding, documenting, and preserving a history of "Destroyed" Benchmarks is an interesting sideline to the hobby.
A water tower would be what is called an "intersection station", and the NGS has indicated that it is no longer interested in reports for them. Also, if you succeed in convincing the NGS that the station is destroyed, then the datasheet becomes inaccessible. Some of us who use datasheets for historical purposes prefer that the datasheets remain accessible, and one way to do that is to simply submit a "not found" report and state that the tower was removed in 1987.
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The March statistics are available on the statistics page. The maps and counts by county have been updated also.
There were 420 datasheets updated with GEOCAC recovery logs. The most recent recovery added to the datasheets was dated February 28.
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I am doing a lot of work (brought on by an excess of benchmark hunting) finding and describing the features of the Boston Harbor Defenses from WW2. The Army (the Coast Artillery, actually) had a local coordinate system for describing these features. Below is a schematic map of the coordinate system, from 1943.
I would like to be able to find the lat/long of items for which I have coordinates (e.g., individual guns). I could easily pull together a number of pairs of Army coordinates vs. lat/long for certain points (benchmarks, in fact--like fire control tower positions). Can anyone tell me how to come up with a (hopefully simple :-) system for doing the conversion for any set of Army coordinates?
Thanks,
-Paul
A long time ago there was a thread on the WWII military grid that preceded UTM. The thread starts off with a lot of guesswork, but by the end, some research had uncovered a lot of useful information.
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Hi Jim,
Our first NGS submission has made it to an NGS datasheet. (date = 1/31/2010)
It was in Yamhill county Oregon and logged under GEOCAC.
I can't find it in your statistics. Can you tell me where to look?
Thanks
I pull the datasheets by month because the NGS page only allows retrieval for a single month, so I got all updates up to and including Feb 28. Even though your recovery report was dated Jan 31, the NGS may not have updated the datasheet until March. The most recent recovery report that was included in the updates was dated Jan 30.
What initials did you use on your submission and what was the PID? If you use the same initials as someone else, the recoveries will be counted as theirs unless I am able to set up some kind of rule that separates them by state and county.
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The February statistics are available on the statistics page. The maps and counts by county have been updated also.
There were 315 datasheets updated with GEOCAC recovery logs. The most recent recovery added to the datasheets was dated January 30.
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It appears from what Holograph tells us that the accuracy of some of the old points isn't as good as the difference due to ellipsoid shape.
Also, many of the published coordinates for the older datums only list to the nearest tenth of a second, which amounts to roughly +/-5 feet. It isn't reasonable to expect any greater accuracy in that case, unless you average a large number of points.
July Statistics
in Benchmarking
Posted
I downloaded all the datasheets that were updated in July, and found no new GEOCAC recovery reports. It looks like the NGS has a backlog. I'll get around to posting the Geocaching.com statistics this weekend.