Errors on geocaching.com/mark

[+tireman]

Went looking for BM Saturday with some newbie friends. Found three. However there are numerous errors on geocaching.com/mark site.

It appears that information was copied incorrectly from NGS info as two BM have identical word description

 

I found three disk benchmarks on pier. Took average of 25 location readings from Etrex Legend Aug 29 2009 to improve accuracy.

 

My readings

Closest to land with markings 606-92 at N41 23.886 W82 33.022 Avg of 25

 

Third near Cache GCZ8BF markings scraped off N41 24.032 W82 32.847 Avg of 25

 

Mid-way our next to pilon at bend in pier with markings 15-92 N41 24.001 W82 32.878

NOTE this location was re-constructed from track as I overwrote Location on my GPS.

I have pictures of these three BM.

 

Web Listings appear to have errors.

 

MC0943 N 41° 23.883 W 082° 33.000

NGS Description -AT THE SOUTHWEST END OF THE CONCRETE PIER EXTENDING OUT INTO LAKE ERIE,

NOTE this LAT-LON places the benchmark about 67' out in the water.

 

MC0944 N 41° 23.883 W 082° 33.017

NGS Description -AT THE SOUTHWEST END OF THE CONCRETE PIER EXTENDING OUT INTO LAKE ERIE,

NOTE this description is the same as MC0943

 

MC0945 N 41° 23.850 W 082° 33.100

NGS Description - HURON, NEAR THE JUNCTION OF WILLIAMS AND WALL STREETS, AT HOUSE NUMBER 111 (A TWO-STORY WHITE HOUSE) SET IN THE CONCRETE BULKHEAD ON THE NORTHEAST SIDE OF THE HOUSE

How can people Log a BM and provide a picture of a BM 1500 feet away?

 

How do we get the web site information corrected to get closer to physical location of BM with 15-92 markings?

 

How do we get the word descriptions fixed?

 

I understand that caches have an "owner". Who "owns" the info on geocaching.com/mark ?

[andylphoto]

tireman,

 

There are a couple different things going on here. First, no one "owns" the listings for benchmarks on geocaching. The database available here is a snapshot of what the NGS database looked at in 2000. Any updates on the gc.com web site must come from user logs. A careful reading of the description should lead you right to the mark if the area has not changed significantly since the mark was placed. The coordinates are a different story.

 

The first two marks both have scaled coordinates. 67 feet off really isn't that bad, considering. The coordinates were derived from someone reading the description, plotting the location (based on the description) on a topographic map, then scaling the coordinates for that particular point. Depending on how accurately the location can be pinpointed on the map, errors of several hundred feet aren't uncommon for scaled coordinates. (See the "Me First" pinned topic at the top of the Benchmarking forum for more info.)

 

The descriptions for the first two marks are not the same. Both happen to be in the same general area (the southwest end of the pier) but a careful reading of the complete descriptions and the designation (what is stamped on the disks) indicates that they are two separate disks on the pier. Here are the "official" NGS data sheets:

 

MC0943

MC0944

 

Regarding the third one, where people are logging a disc 1500 feet away, see the discussion in this thread about that exact problem. It happens frequently, and people don't care--even when the error is pointed out, many continue to log "finds" on the wrong mark.

 

EDIT: Just looked closer at the description vs. the coordinates. The error is more than the 67 feet I see--looks like several hundred, but still not uncommon for a scaled entry. When you post a log for a mark, you have the option of adding a waypoint. This doesn't update the coordinates on the benchmark page, but lets others know that there are better coordinates available.

Edited August 31, 2009 by andylphoto

[+LSUFan]

Tireman, welcome to the world of benchmarking. It is a lot more challenging than hunting for geocaches...and a different beast all together. There is lot to learn, in order to do it correctly.....but it isn't real difficult. You'll have the fundamentals down in no time.

 

Andylphoto, gave some great links on where to begin the education. You especially want to learn the differences between scaled coordinates and adjusted coordinates.

 

Holograph has a great wiki too on getting started:

 

http://www.holoscenes.com/cgi-bin/moin.cgi/FirstTime

 

Let us know how it goes.

Edited August 31, 2009 by LSUFan

[+Black Dog Trackers]

Hi tireman -

 

Concerning MC0943, the datasheet says the designation of the mark is: "906 3074 WL 108 USLS" The mark must have this designation stamped on it to be a find of MC0943. Also, the history of this mark says that it was monumented by USLS (United States Lake Survey, according to this list). The "monumented by" is not always totally accurate, though. The history does say that the mark was monumented in 1935, but the disk pictured is year 92 (1992). If you click on "view original datasheet" on the geocaching benchmark's page, you will see a "STAMPING" variable and the disk must say the same exact thing to be a find. So, the disk pictured is not MC0943. Instead it is a US Army Corps of Engineers disk monumented in 1992 with the designation 606. It is likely that MC0943 is gone.

 

Concerning MC0944, the same problem exists. The MC0944 disk is a US Engineers (predecessor of US Army Corps of Engineers) disk with a stamping of "909 S4". The disk pictured is a US Army Corps of Engineers disk with a stamping of "15 92". The most recent report of MC0944 is 1980, 12 years before the disk pictured was mounted.

 

Concerning MC0945, the designation (the identity of this particular disk) is "906 3074 D". The monumentation note says NOS, which is the National Ocean Survey. The designation has been worn off the disk pictured, but it certainly isn't a NOS disk. It is another US Army Corps of Engineers disk instead.

 

So, the situation here is not the datasheets that are in error, it is the 'finds' that are in error. The disks pictured are not finds, so the find logs are wrong. Unfortunately, it appears that the disks described in the datasheets are gone. Not necessarily so, however - they still might be hiding there! It is important to remember that there are hundreds of thousands of disks that are not in the database we use, and many of them are fairly near where the ones we are hunting were located.

 

Benchmark hunting is tricky and sometimes very challenging. Unlike geocaching, what you're looking for might have been gone for 50 years or more, so there's a psychological challenge too.

 

The benchmark hunting FAQ is another good place to read about benchmark hunting. In particular, in the cases you brought up, there is an article about making sure you found the right disk. Another very important thing to know about right way is the difference between scaled and adjusted location disks. Also, since you found 3 disks that are not in the database we use, you could read about that here.

 

I hope this helps solve this puzzle of 3 disks and hope you have more good hunting in the future!

[AZcachemeister]

Greetings tireman!

 

See the above posts about scaled marks.

If you continue very long at this, reading and interpreting the verbal descriptions will become second nature, and the GPS will only be a tool to get you in the right area...which indeed is all the co-ordinates for a scaled mark are supposed to do.

 

As for the question of ownership...

There is nobody (who cares) with the power to delete erroneous, mistaken, or downright fraudulent logs.

Some marks just seem to attract incorrect logs, and once someone logs it, everyone else who comes along just follows suit. Usually cachers happen to see a disk, record the co-ordinates, and log a find on the nearest benchmark...regardless of whether or not it is the proper mark in question.

Occasionally it can be an opportunity to point out a mistake, and some folks will appreciate the tutelage.

In all too many cases the loggers won't care what your opinion might be, even when you point out the fact that the stampings on the mark in their photo do not match those in the description.

 

All we can do is take several deep breaths, and move on.

[+pgrig]

Nice coaching, guys, and excellent explanations!

 

-Paul

[+tireman]

Thanks to all who responded

 

I think I better understand the situation. I think I will go back to the three BM in question.

I will post as NOT FOUND but add the information about the Corp of Engineer disks.

Maybe add the link to Holograph's wiki and to the Waymark site so others can educate themselvs if they want.

 

Thanks again