Discrepancies between datasheet descriptions and observations/recoveries

[ipuppy]

I'm new to benchmarking, and am enjoying it a lot. I've tried to learn as much as I can, reading the information on the GC site, browsing these forums and reviewing others' logs. I'm trying to be pretty conservative in my logs, with the plan to submit recoveries to NGS in the future, once I feel much more proficient.

 

On a recent benchmarking run while on a work trip to Vicksburg, Mississippi I had several potential finds that I could not justify claiming, but that raise some questions. In all cases, the object I observed did not clearly match the description in the datasheet. However, there were recently logged finds and recoveries on the datasheets that apparently used the same descriptions. Here are some specifics:

 

CP2774 - VICKSBURG STANDPIPE. Obviously the standpipe is long gone, however there is a communications tower on the old site which has been recovered as "good" with a note that the tower is directly over the standpipe foundation. Is this good enough? Wouldn't the old station (standpipe) be considered "destroyed" and a new station created, with a new PID?

 

CP2764 - VICKSBURG N MUNICIPAL TANK. In the datasheet the tank is described in early recoveries (1959 and 1967) as having six legs, but a more recent recovery states it has 8 legs, with no additional information (e.g., were these modifications to the original tank or a replacement of the entire structure?). To further confuse the issue my observations, unfortunately in rapidly dwindling daylight and from a bit of a distance, show the tank with 4 legs. The position I observed (again, from a distance) matches with that on the datasheet, so I'm pretty sure I have the right location (i.e., what I saw is not a tank in another part of town - as is my suspicion of some of the other log entries). Again, shouldn't this have been recovered as "destroyed" and a new station with PID and datasheet created?

 

CP2763 - VICKSBURG CORPS ENG RADIO MAST. The datasheet description is of a tower with four legs. I pretty clearly observed (although, again, after sunset) a three-legged tower. Same questions - was the old one destroyed and the new one a new station? CP2759 is a similar situation; the mast observed differs from that described/recovered.

 

Is a recovery in the datasheet that describes a major change to a station enough evidence that the station has changed? Does the recovery submission process include any sort of verification beyond what is apparent in the datasheet?

 

Thanks to all in this forum for sharing your knowledge and experience, and I look forward to your input. Your review and comments on my other logs is also welcome. Happy hunting!

ipuppy

[Bill93]

A new tower or tank is unlikely to be over the same spot to sufficient precision, and so the old position is destroyed. It is the position, not the object that counts.

 

NGS no longer wants reports on Intersection Stations such as spires, tanks, towrs, etc. unless you can submit sufficient proof that they are destroyed so they can clean up the database. Professionals rarely use them because their precision is inadequate for most uses. They may supply a convenient backsight angle for measurements but they won't be relied on for absolute position.

 

Usually it is sufficient proof to state that within handheld GPS precision the coordinates the described object is no longer there AND submit a photo of remains (maybe concrete pads), or something newer at the location, especially if there is a nameplate showing a new water tank was built after the monumentation date on the data sheet, or it is a watersphere instead of a tank on legs, or unambiguous references like tower on the south side of X street and now people are logging one on the north side.

 

It might be the describer's mistake or yours if the only discrepancy is 6 vs 8 legs or 3 vs 4. See if you can corroborate the age of the object.

 

Before and after pictures showing the same background are good. Sometimes newspaper archives or local history books can supply the "before" shot.

 

On the GC site, you can post destroyed reports and notes until your fingers are tired of typing and some people will still log any nearby object regardless of the discrepancies you have pointed out.

[ArtMan]

To try to resolve the discrepancy on CP2764 - VICKSBURG N MUNICIPAL TANK as to the number of legs, Microsoft's map site (maps.live.com) has the very useful "bird's eye view" feature, which has aerial photos from an angle, rather than straight down, as you get in Google Maps. You can get up to four different view (from different directions) of the same place.

 

In this case, the "current" water tower does, in fact, seem to have four legs, not six as described on the datasheet. Also, I think the tank is not the type described as "ellipsoidal."

 

(I put "current" in quotes in the previous paragraph because neither Google nor Microsoft identify the date, or even the year, the photograph was taken. The copyright dates are not reliable. In general you can probably assume photos are not more than a few years old, but I suspect many may be quite a bit older than that.)

 

In the case of intersection stations (water towers, chimneys, church spires, etc.), I would not be very trustful of logs on geocaching.com. As in the case of benchmark disks located near caches, these benchmarks tend to attract people who are primarily geocachers. No disrespect intended to cachers at all, but there is a certain amount of specialized knowledge involved in looking for benchmarks that general geocachers may lack, and this contributes to a large number of false "found" reports for reasons discussed from time to time in this forum.

 

-ArtMan-

[+m&h]

Google Earth Pro usually includes an "imagery date" as well as the more recent copyright year. Its shot of this tank, which indeed has four legs, carries an imagery date of March 8, 2006.

 

This imagery date feature, incidentally, enables GE Pro to do chronological slide shows of all the different shots of a given area.

 

Cheers,

[+m&h]

A postscript, after several minutes of fiddling around. The oldest available shot of this location on GE Pro is dated February 12, 1996, and appears to show the same tank as the most recent shot, though from a slightly different angle. Not fiercely sharp, but four legs still looks right.

 

Another by the way: the historical imagery feature may be available in the latest free version of Google Earth. We haven't checked that.

 

Cheers,

[ipuppy]

Bill93, ArtMan, M&H-

I didn't realize intersection stations were rarely used and that NGS doesn't really want submissions on them. I've kind of had a bias toward finding marks so I'll keep working on those and focus my future recovery report efforts there.

Thanks for the suggestions on verifying identity. I've done a little poking around to try to find historical photos. I'm currently looking for images of the Western Maryland RR yard in South Baltimore to confirm my find of JV5544, and also of Camden Station, location of JV0562, to see if I misidentified the columns mentioned in the description. I've done some online searching for historical images, with limited success and am considering a trip to the Pratt Library, which I hear has a substantial historical image collection. Any suggestions for sources of historical images is appreciated, particularly those online.

I definitely have seen some less-than-diligent entries in the geocaching.com logs, and I'm sure some of my entries could be better. I plan to review them as I get more experience and hopefully get better. i have to say, I've been finding a lot of ArtMan's finds, and kind of look to his entries as a benchmark (pun intended) for quality.

Thanks again-

ipuppy

[+jwahl]

CP2763 plots about 35-40 feet east of the current tower in google earth, based on those buildings that are now underneath the tower. And it is now clearly a 3 legged tower. However discrepancies do appear in descriptions. A good look can be seen in birds eye view from MS live search and compared to a google earth view with the stations coordinates plotted.

 

That is not conclusive because these photos are not always correct or fully corrected. For example terraserver older b/w imagery shows what is probably a 3 legged tower over the buildings at the correct coordinate.

 

- jlw

Edited February 16, 2009 by jwahl

[Wintertime]

"ipuppy" (sorry, I don't know your real name to address you properly), I notice that the most recent NGS logs for all three of the stations you cited were made by the U.S. Power Squadron (USPSQD), a recreational boating organization. Although those of us who've been benchmarking for quite a while have seen some superb reports from certain USPSQD people, we have also seen some terribly sloppy reports. The bottom line is that, unless you can tell from the person's initials that a certain report was made by someone with a good track record, you should always take reports from amateurs with caution. (Even the pros sometimes make mistakes, but at a much lower percentage. :-) )

 

I see also that all three stations have Found reports on Geocaching.com. Again, as you noted, there is a huge variability in the quality of benchmark reports by geocachers. I have a few bete noirs in my area--stations that cachers keep reporting as found no matter how many times a more knowledgeable cacher points out that the station was long since destroyed and they're seeing replacements. (Some of those, incidentally, are intersection stations--as are your three--while others are actual disks.)

 

I applaud your efforts to research historical data to verify whether an intersection station is the original, even without the motivation of filing a report with the NGS. If you get frustrated with that amount of work, you might want to take a break and look for some disks. Sometimes they can fool you, too, but not as often as intersection stations. :-)

 

Good luck!

 

Patty