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Grasscatcher

What Is Going On?

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In Mesa Co Colorado, one of the BM in Colo National Monument is a BM with ID KMO 444 - FRUITA.

 

Just as a project, I took on finding all six USGS BM within the Natl Monument. Some didn't have any record of being found since they were monumented in 1934, so I thought it would be fun. Some were easy, easy and others were long hikes and steep climbs, but that's what I love to do so......

 

In the process of finding all six, I just uploaded the coordinates for the station itself from the original data sheets into my GPS. I didn't bother uploading the ref mark coordinates or even necessarily look for the marks, but did stumble across several in the process of finding the stations. The BM all have adjusted coordinates and were found in good shape.

 

After finding all six over a period of time, it dawned on me that I should have found all the Ref Marks while I was at it....DUH ! Oh well, it was all about being "out", and the hikes, and the challenge, so I noted all of the ref marks that I hadn't already stumbled across, and plotted them from their distances and bearings and datum taken from the orig data sheets.

 

Yesterday, after a couple of previous trips failed to find any of the missing ref marks at a couple of the stations,the weather was perfect and I was DETERMINED.

 

For this FRUITA station I found both Ref marks and my coordinates agree with the Ref mark coordinates posted by a previous finder and published on the Groundspeak Data sheet......but compare those coordinates with the orig data sheet "location" established by dist and bearing.

BIG difference!

If I had used the previous finders coordinates, I would have walked right straight to both!....

but instead I used "official" data I thought would eliminate any possible error.

 

I can't find any combination of bearing error, magnetic vs true error,Datum error, N vs S or E vs W error, or anything else that makes sense.

 

Can someone else plot the Ref mark locations (for KMO444) from the orig data sheet and compare with the Prev Finders locations on the GS data sheet (also below)? I'm stumped........Did I screw up or are the orig data sheet location descriptions wrong?

 

Below are my “as calculated” and the actuals (as found)

 

Fruita Ref 1 39 05.23556 -108 43.95456 3/22/2013

Fruita Ref 1 Act 39 05.22600 -108 43.97304 6464.101 3/22/2013

 

Fruita Ref 2 39 05.23396 -108 43.96527 3/22/2013

Fruita Ref 2 Act 39 05.21820 -108 43.95546 6448.599 3/22/2013

 

….and the previous finders locs…

 

RM1 N 39° 05.227' W 108° 43.975'

RM2 N 39° 05.220' W 108° 43.956'

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In Mesa Co Colorado, one of the BM in Colo National Monument is a BM with ID KMO 444 - FRUITA.

 

so I noted all of the ref marks that I hadn't already stumbled across, and plotted them from their distances and bearings and datum taken from the orig data sheets.

 

 

For this FRUITA station I found both Ref marks and my coordinates agree with the Ref mark coordinates posted by a previous finder and published on the Groundspeak Data sheet......but compare those coordinates with the orig data sheet "location" established by dist and bearing.

BIG difference!

If I had used the previous finders coordinates, I would have walked right straight to both!....

but instead I used "official" data I thought would eliminate any possible error.

 

I can't find any combination of bearing error, magnetic vs true error,Datum error, N vs S or E vs W error, or anything else that makes sense.

 

I guess the first question is what exactly did you use to plot the reference marks coordinates by their distance and bearings from the main station?

 

The NGS does have software to help with calculations like this.

 

http://www.ngs.noaa.gov/PC_PROD/Inv_Fwd/

Edited by LSUFan

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Using the coordinates for the main station and RM1 in Inverse you get the following:

 

 Ellipsoid : GRS80 / WGS84  (NAD83)
 Equatorial axis,    a   =    6378137.0000
 Polar axis,         b   =    6356752.3141
 Inverse flattening, 1/f =  298.25722210088

  First  Station :
  ----------------
   LAT =  39  5 13.48983 North
   LON = 108 43 57.62473 West

  Second Station :
  ----------------
   LAT =  39  5 13.60000 North
   LON = 108 43 58.50000 West

 Forward azimuth        FAZ = 279 10 28.5064 From North
 Back azimuth           BAZ =  99 10 27.9546 From North
 Ellipsoidal distance     S =        21.3083 m

 

And the results for RM2:

 Ellipsoid : GRS80 / WGS84  (NAD83)
 Equatorial axis,    a   =    6378137.0000
 Polar axis,         b   =    6356752.3141
 Inverse flattening, 1/f =  298.25722210088

  First  Station :
  ----------------
   LAT =  39  5 13.48983 North
   LON = 108 43 57.62473 West

  Second Station :
  ----------------
   LAT =  39  5 13.20000 North
   LON = 108 43 57.30000 West

 Forward azimuth        FAZ = 138 52 22.7606 From North
 Back azimuth           BAZ = 318 52 22.9653 From North
 Ellipsoidal distance     S =        11.8656 m

 

Not totally sure I know how to use Forward, so I'll skip that one. Since this mark doesn't have a proper box score, DSWorld's compute RM position function won't work on it. (Same for NGS>GPX I think.)

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Using the coordinates for the main station and RM1 in Inverse you get the following:

 

 Ellipsoid : GRS80 / WGS84  (NAD83)
 Equatorial axis,    a   =    6378137.0000
 Polar axis,         b   =    6356752.3141
 Inverse flattening, 1/f =  298.25722210088

  First  Station :
  ----------------
   LAT =  39  5 13.48983 North
   LON = 108 43 57.62473 West

  Second Station :
  ----------------
   LAT =  39  5 13.60000 North
   LON = 108 43 58.50000 West

 Forward azimuth        FAZ = 279 10 28.5064 From North
 Back azimuth           BAZ =  99 10 27.9546 From North
 Ellipsoidal distance     S =        21.3083 m

 

And the results for RM2:

 Ellipsoid : GRS80 / WGS84  (NAD83)
 Equatorial axis,    a   =    6378137.0000
 Polar axis,         b   =    6356752.3141
 Inverse flattening, 1/f =  298.25722210088

  First  Station :
  ----------------
   LAT =  39  5 13.48983 North
   LON = 108 43 57.62473 West

  Second Station :
  ----------------
   LAT =  39  5 13.20000 North
   LON = 108 43 57.30000 West

 Forward azimuth        FAZ = 138 52 22.7606 From North
 Back azimuth           BAZ = 318 52 22.9653 From North
 Ellipsoidal distance     S =        11.8656 m

 

Not totally sure I know how to use Forward, so I'll skip that one. Since this mark doesn't have a proper box score, DSWorld's compute RM position function won't work on it. (Same for NGS>GPX I think.)

 

Good deal EdrickV. When you take the numbers you posted after running the INVERSE, then converting the degree,min, sec format to decimal minutes......the numbers come up to be (as I always just take the seconds and divide by sixty to get decimal minutes)

 

RM 1- 39 05.22666 (or .227 rounded), -108 43.975

RM 2- 39 05.220, -108 43.955

 

These numbers almost match exactly the numbers posted by the geocaching logger and Grasscatchers actual gps numbers (which handheld gps isn't usually that accurate). <_<

 

So GrassCatcher, it appears that something may have been amiss in your original plotting of the reference marks.

Edited by LSUFan

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What I used to plot the Ref marks was Expert GPS by Topografix. I took the original data sheet coordinates for KMO444 and input the Bearing and Distance for each Ref mark and EGPS then projected a new waypoint FROM the KMO444 location TO the "supposed" Ref mark location.

 

The data sheet clearly states or "says".....the Ref marks are.. FROM the station NORTH 29/25 deg X min E/W... 59/50 ft.

 

....yet when plotted to actual coordinates Both are "physically" SOUTH of KMO444.

 

I know my coordinates (and yours) are "accurate" (for a GPS) for the actual Ref mark locations.

It's just that I think the verbage describing their locations is incorrect.

 

I'll work with the programs you referenced this afternoon. Maybe it will become clearer then.

 

Thanks.

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What I used to plot the Ref marks was Expert GPS by Topografix. I took the original data sheet coordinates for KMO444 and input the Bearing and Distance for each Ref mark and EGPS then projected a new waypoint FROM the KMO444 location TO the "supposed" Ref mark location.

 

The data sheet clearly states or "says".....the Ref marks are.. FROM the station NORTH 29/25 deg X min E/W... 59/50 ft.

 

....yet when plotted to actual coordinates Both are "physically" SOUTH of KMO444.

 

I know my coordinates (and yours) are "accurate" (for a GPS) for the actual Ref mark locations.

It's just that I think the verbage describing their locations is incorrect.

 

I'll work with the programs you referenced this afternoon. Maybe it will become clearer then.

 

Thanks.

 

OK, I think I misread what EdrickV did. It appears he took the posted coordinate numbers, and then got the bearings for them from the station. That makes sense on why the gps numbers were too perfect.

 

I'll look at the datasheet and see what I can make from it. Yes, there are sometimes error in the datasheets (which you may very well have), as well as numbers getting transcribed wrong when the datasheets were keyed into a computer. I have found some marks listed in the wrong county as well as the wrong state.

Edited by LSUFan

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OK, here's the latest..

 

I used the FORWARD online calculation tool posted above.

After converting the Orig Data sheet Ref Mark bearings to azimuth, and the data sheet distances to meters, the coordinates calculated for the ref marks, EXACTLY matched the coordinates I had previously obtained by using Expert GPS. Good information to know....

 

Ref 1-Calculated from Datasheet----Ref 1 Actual (GPS)

39 05 14.01714 ---------------- 39 05 13.6

108 43 57.302------------------- 108 43 58.4

 

Ref 2-Calculated from Datasheet---- Ref 2 Actual (GPS)

39 05 13.92138-------------------- 39 05 13.1

108 43 57.93632-------------------- 108 43 57.9

 

Both calculated positions plot North of station and are described as being North of station on datasheet.

 

Both marks are, in fact , South of the KMO444 station.

 

Does anyone agree that the Datasheet description must be incorrect?

 

Thanks.

Edited by Grasscatcher

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Grasscatcher,

 

Did you take photos showing the relative positions to/from the Tri Station and the RMs?

 

Which RM is easterly or westerly of the Tri? kayakbird

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Assuming the results of Forward don't match the results above from Inverse, then yeah it sounds like something is wrong. Unless we're somehow misinterpreting what the datasheet is saying. Inverse just takes two sets of coordinates and gives info like I posted above, so those were the main station coordinates from the datasheet and the RM coordinates from Grasscatcher's recovery report. Forward is the one that you do the other way around, and I wasn't sure what info to put where.

Edited by EdrickV

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I've got pics that show actual disks but not positions relative to each other.

 

....but with all four plotted on the same map if you assumed a "clock" shape, with KMO444 being centered, with 12 as North....

 

Ref 2 calculated is about 10 and Ref 2 act is about 5.

 

Ref 1 calculated is about 2 and Ref 1 act is about 8.

 

I wish I could attach a gpx file or a jpg file.

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Grasscatcher,

 

Reciprocal bearings to RM's is a fairly common Data Sheet error - I think that there was a good thread here on that subject a couple of years ago.

 

This one, also in Mesa County, Colorado

 

3d5072ef-4b28-4cfb-a41a-861a2f087e11.jpg

is one of my favorites. RM's are pegged on Google Earth at the found HH2.

 

kayakbird

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I made up a quick, ball park projection, from the data sheet, on my 60Cx.

59.10 ft 25 deg from KMO444, shows 39 05 14.0 108 43 57.3 for Ref 1.

50.10 ft 331 deg from KMO444, shows 39 05 13.9 108 43 57.9 for Ref 2.

 

Ball park, but close to the previous finder.

 

I'm just across the border, and less than 75 miles away, and about 100 feet higher than that location, so I can say that

Grasscatcher chose a good day to search, as the next day started out at 14 deg and was windy! Todays 7 was a piece of cake compared with what see on the TV, that is headed East.

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Both marks are, in fact , South of the KMO444 station.

 

Does anyone agree that the Datasheet description must be incorrect?

 

Thanks.

 

"KM0444''REFERENCE MARK NO. 1--STANDARD BRONZE REFERENCE TABLET SET IN SOLID

KM0444''ROCK, 59.10 FT. FROM STATION, N 25 DEG 29 MIN E. KM0444''

KM0444''REFERENCE MARK NO. 2--STANDARD BRONZE REFERENCE TABLET SET IN SOLID

KM0444''ROCK, 50.10 FT. FROM STATION, N 29 DEG 22 MIN W."

 

If you read the datasheet and change the "comma" after "STATION" to "WHICH IS" then it reads correctly. So the directions read "50.10 FT FROM STATION WHICH IS N 29 DEG 22 MIN W OF THE RM 2".

 

If it was spoken, then you would know that the person who wrote the description meant that the station was north of the RM.

 

John

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Both marks are, in fact , South of the KMO444 station.

 

Does anyone agree that the Datasheet description must be incorrect?

 

Thanks.

 

"KM0444''REFERENCE MARK NO. 1--STANDARD BRONZE REFERENCE TABLET SET IN SOLID

KM0444''ROCK, 59.10 FT. FROM STATION, N 25 DEG 29 MIN E. KM0444''

KM0444''REFERENCE MARK NO. 2--STANDARD BRONZE REFERENCE TABLET SET IN SOLID

KM0444''ROCK, 50.10 FT. FROM STATION, N 29 DEG 22 MIN W."

 

If you read the datasheet and change the "comma" after "STATION" to "WHICH IS" then it reads correctly. So the directions read "50.10 FT FROM STATION WHICH IS N 29 DEG 22 MIN W OF THE RM 2".

 

If it was spoken, then you would know that the person who wrote the description meant that the station was north of the RM.

 

John

 

Forgot to add that the direction from the RMs is stated as DEG, MIN E (of north) and DEG MIN W (of north).

 

John

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@ 2 OF,

Well, that's one of those deals where, if the Datasheet said something different, it would be a different location....HA! ...but in this case that theory doesn't locate them correctly either.

 

That's one of the first things I thought of because I've plotted hundreds and hundreds of irrigation ditch structures from their legal descriptions which often read...."located at a point ...from whence the XX corner of Sect xx bears x deg x min etc" which means, (the same as what you're saying), that you have to start with the sect corner, reverse the quadrant bearings and distance and, in essence ,work backwards to locate the structure. That doesn't work on this one. It makes one of them closer but the other one is still "off the wall". They are not reciprocals.

 

Plot them both and you'll see what I'm saying.

Edited by Grasscatcher

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@ 2 OF,

Well, that's one of those deals where, if the Datasheet said something different, it would be a different location....HA! ...but in this case that theory doesn't locate them correctly either.

 

That's one of the first things I thought of because I've plotted hundreds and hundreds of irrigation ditch structures from their legal descriptions which often read...."located at a point ...from whence the XX corner of Sect xx bears x deg x min etc" which means, (the same as what you're saying), that you have to start with the sect corner, reverse the quadrant bearings and distance and, in essence ,work backwards to locate the structure. That doesn't work on this one. It makes one of them closer but the other one is still "off the wall". They are not reciprocals.

 

Plot them both and you'll see what I'm saying.

 

Did you plot the station from (RM1) at 25° 29' and the station from (RM2) at 330° 38'?

 

John

 

Edited to designate the direction from each RM.

Edited by 2oldfarts (the rockhounders)

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Being this is a USGS mark, you can contact their office. They will actually go to their file cabinet and get out the original documentation for the mark, to send you a copy. That way you can see if their reference mark description is different from what the NGS keyed into their online database.

 

The following was taken from the USGS website:

 

How can I find survey benchmark information?

 

Depending on what survey benchmark information you're looking for will determine where to look. Most survey benchmarks were not established by the U.S. Geological Survey, but, instead by the National Geodetic Survey, and are available on their website at www.ngs.noaa.gov. From there, click on the "Datasheets" link at the top of the page and navigate the subsequent retrieval links. If you need further assistance you can call 301-713-3242 or e-mail infocenter@ngs.noaa.gov.

 

As for USGS survey benchmark data, this is not yet available online. However, you can still inquire about the USGS benchmark information from two sources. For the Eastern U.S. vertical and horizontal control information contact the USGS in Rolla, Missouri, by calling 573-308-3500 or e-mailing mcmcesic@usgs.gov. For Western U.S. vertical and horizontal control information, contact the USGS in Denver, Colorado, by telephone at 303-202-4400 or by e-mail at infoservices@usgs.gov.

Edited by LSUFan

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@ 2 OF,

Well, that's one of those deals where, if the Datasheet said something different, it would be a different location....HA! ...but in this case that theory doesn't locate them correctly either.

 

That's one of the first things I thought of because I've plotted hundreds and hundreds of irrigation ditch structures from their legal descriptions which often read...."located at a point ...from whence the XX corner of Sect xx bears x deg x min etc" which means, (the same as what you're saying), that you have to start with the sect corner, reverse the quadrant bearings and distance and, in essence ,work backwards to locate the structure. That doesn't work on this one. It makes one of them closer but the other one is still "off the wall". They are not reciprocals.

 

Plot them both and you'll see what I'm saying.

 

John,

Yes, I used

 

Did you plot the station from (RM1) at 25° 29' and the station from (RM2) at 330° 38'?

 

John

 

Edited to designate the direction from each RM.

 

Yes, I used the 25 29, and 330 38 as azimuth.

 

Here's the latest....Today I hiked to nearby KMO443 to get the Ref marks there. I had looked for them previously but did not find. Today however, because of your suggestion, in addition to the "data sheet" locations. I had also entered the reciprocals for them.

I found both marks at their reciprocal locations! Pre trip calculated GPS coordinates were within 2 meters (I use UTM coords) of "actuals" found and recorded.

 

I went back and recalculated the data for both marks of KMO444 exactly the same way (as 443 today). No good, they are NOT reciprocals. I have just come to the conclusion that both of 444's Ref marks definitely "have a datasheet problem". No combination of errors or transposition can explain.

 

The sun will still come up in the East tomorrow anyway.....

 

Thanks for your help.

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Might be trying to turn sow's ears into silk purses here.

 

RM's are not measured to the accuracy of the parent Triangulation Station. They are meant to be a guide to assist in the location of the Tri.

 

I think that most of us can come up with examples where the obviously original, undisturbed, RM's are found several degrees and feet from the published information - to say nothing of the many, many that are on a reciprocal bearing.

 

kayakbird

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