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A Little Help Please


Airmapper
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I know, I'm always asking for something in here, but I'd like to get some advice from some people who know.

 

This is the first BM I logged, I found RM 1, and he main mark, but not RM 2, and an Azimuth marker. I am assuming there are 4 markers total, 2 of which I've found, and 2 still out there.

 

I need some help figuring out my bearings and trying to find the other marks. I looked for RM 2 today, and came up empty, BUT there was a lot of obstacles and changes to throw me off. Also, is there a general rule of thumb on how far, and at what angle a triangulation stations markers will be apart? (Using the description, and standing on the main mark DALLAM 1950, I guessed an angle of about 10 degrees between RM 1&2, isn't that a little close?)

 

Any BM hunting advice will be appreciated, even if it's just in general. Thanks in advance.

 

In case you want to see the BM info...

http://www.geocaching.com/mark/details.aspx?PID=HA1438

 

  Documented History (by the NGS)

1/1/1950 by CGS (MONUMENTED)

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

1/1/1952 by CGS (GOOD)

RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1952 (LWS) STATION WAS RECOVERED AS DESCRIBED AND ALL MARKS WERE FOUND TO BE IN GOOD CONDITION. THE DISTANCE TO REFERENCE MARK NO. 2 FAILED TO CHECK THE DIRECTION TO AZIMUTH MARK AND REFERENCE MARK NO. 1 FAILED TO CHECK. THE OLD DESCRIPTION IS ADEQUATE. HEIGHT OF LIGHT ABOVE STATION MARK 26 METERS.

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Airmapper,

For help with finding the RMs and AZ mark, you need to look at the actual NGS datasheet. You can use the quick "actual datasheet" link on the Geocaching site, or go to the NGS PID database.

Once you have the real datasheet, look for something called the "box score". This is an outlined area that contains information on the reference markers and other stations used as reference. For your PID, HA1438, the box score is:

 

HA1438|---------------------------------------------------------------------|

HA1438| PID    Reference Object                    Distance      Geod. Az  |

HA1438|                                                          dddmmss.s |

HA1438| CG8461 DALLAM AZ MK                                      1024453.2 |

HA1438| CG8463 DALLAM RM 2                          27.664 METERS 21854    |

HA1438| CG8462 DALLAM RM 1                          25.096 METERS 32233    |

HA1438|---------------------------------------------------------------------|

HA1438

 

You will see that the RMs and AZ MK are listed, with a distance from the main station disk and an angle measurement. I think the RMs are measured in DDDmm, clockwise from north.

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That makes sense, thanks.

 

I found RM1 and the magnetic heading is quite possibly 322 degrees. (North North- West) If I'm reading that right. That is very close if not exactly the way I found it.

 

That would make RM 2 @ 218 degrees (South- West) @ 25.096 meters. That places it in an open area that I haven't focused any attention on. (Was too busy bushwacking north of there) That also makes some sense, as the extent of said graveyard may not have been on both sides of the road like it is now.

 

Is there only 3 marks? Is the AZ mark and the "main mark DALLAM 1950" one and the same? I think I got confused and assumed the AZ mark was a fourth mark.

Edited by Airmapper
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Airmapper -

 

In addition to all the above, if you draw a line a bit south of due east from the church, you will note that it crosses the Beechland-Quality Road at about 0.3 miles from the church and very near the scaled coordinates that BDT gave, above. That's where your AZ is, I bet. In 1950, the road was described as "gravel", but I bet its paved today.

 

Keep in mind these general rules:

RMs are usually 30 - 150 feet from the station, and usually have the RM "arrow" symbol pointing towards the station.

 

AZs are usually 0.15 to 0.75 miles from the station. The AZ in your case may have the same "DALLUM 1950" STAMPING, but the AZ disk will have an AZ "arrow" symbol pointing towards the station (whereas the triangulation station will have the "triangle with a dot in the mddle" symbol.)

 

I also note (from looking at a MapSource topo), that the station and the AZ appear to be at approximately the same elevation, and a line from the station to the assumed location of the AZ passes over slightly lower terrain. That makes sense and adds strength to my assumption about the location of the AZ. That's how AZs are typically laid out.

 

To get to your AZ from the church, go southeasterly for about 0.21 miles and turn northeast. Go northeast on Beechland-Quality Road for about 700 feet and the AZ on the left (northwest) side of the road. Were I looiking for this AZ, I would leave my handheld set to GOTO the station, and I would travel northeast on Beechland-Quality Road until the tail of my GOTO arrow was on 102 degrees on the compass rose.

 

Finally, BuckBrooke's recommendation (to check the "view original datasheet" or to go to the current NGS page) is a critically good recommendation. You should always check the NGS sheet. I recommend that you always check the datasheet by way of the NGS datasheet page. The "original sheet" that is accessible at the Geocaching datasheet page is four years' out of date, and will not have current recoveries or updates. Not an issue here as the actual/current NGS datasheet has not been updated since it was uploaded to the Geocaching database about four years ago.

 

Please let us know if you find the other RM and the AZ. These kinds of cases are excellent learing exercises.

 

 

Will

Edited by seventhings
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Yes I am learning quite a bit on this one. The others I have done were not nearly as difficult. I have been using the NGS site and datasheets, but was having some trouble interpeting all the data. Thanks to these posts I think I've figured out how to find the RM's using a compass heading and distance.

 

As for the road, you'd be suprised that it was paved this year, and only a few months ago at that. There is a growing amish community nearby, and I think they are what finally got the road paved. (Ironic that they use horses and buggys.)

 

I'm going to keep looking now that I actually know what I'm going after. The description only was difficult to use, but I have a feeling using a compass and GPS I'll have better luck finding the remaining two marks.

 

I'll try to use what I've got to find them, I'll post back here if I have more questions, and if I find them.

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Just a general FYI on azimuth marks.

 

An azimuth is a fixed point of reference to which all other angles are compared to. In essence, it is used as the "zero" for turning angles to other points, RMs and especially other triangulation stations. Think of an azimuth as your north star.

 

I've seen azimuths set at 600 feet or less, although I'm sure there are some minimum distances for azimuth marks. Evenfall or another surveyor here could enlighten us on this particular question. Better yet, an short explaination/diagram of a typical triangulation station would be a great resource for everyone.

 

Airmapper, enjoy finding those last two marks.

 

~ Mitch ~

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I'm 99% certain that surveyors use TRUE north, for geodetic surveys.

 

I've platted property surveys using metes and bounds found in old courthouse deeds dating from the 1820's. At that time, they used magnetic north. It was interesting to see that later surveys of the same property had different bearings and would sway or vary as much as 15 degrees. This was due to the magnetic declination changing over time.

 

~ Mitch ~

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You should find the AZ MARK within 1 meter N/S and a few meters E/W of of these coords:

N 37 01.994, W 86 51.776

N 37 01 59.6, W 86 51 46.6

 

How did I get these numbers? First, view the

TOPOZONE image:

 

a64b3017-3291-4af2-b6e0-68227ce7550a.jpg

 

You can clearly see a BM 677 and a triangle on the map at the likely location of the azimuth mark. If you click in the center of the triangle , you get coords that are accurate to within around 5 meters much of the time. I got UTM 16W 512190E 4098563N. But we can refine the N/S position since we know that the mark is EXACTLY 102d 44m 53.2s from the main mark.

 

Using a program like GEOCALC, find the distance from DALLAM to DALLAM AZ MK:

DALLAM N37 02 02.79099 W086 52 04.05646

DALLAM AZ MK 16W 512190E 4098563N = N 37 01 59.48, W 86 51 46.57

Distance: 1456.485 ft

 

Now project a point 1456.485ft at 102d 44m 53.2s from DALLAM, and you get the new numbers for DALLAM AZ MK : N 37 01 59.6, W 86 51 46.6

 

Do me a favor and if you find the AZ MK, take an average GPS reading and let me know what you get for its coords. Assuming the mark has not been graded away, it should be easy to find since it projects 6 inches.

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I did see that mark on USAPhotomaps and assumed it was an unmarked non NGS marker.

 

Thanks for the info TerraVador I'll get averaged coodrs for that spot and see how close it is, (If it's still there, which it should be.)

 

Now I have some coodrs and headings, I'll have a much better chance of finding those marks.

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UPDATE:

 

I have found all the markers now. The compass heading helped me find RM 2, because apparently the "North end of cemetery" did not extend across the road at that time.

 

Here are some coords I got:

DALLAM 1950 N 37* 02.046

W 086* 52.070

RM 1 N 37* 02.058

W 086* 52.080

RM 2 N 37* 02.036

W 086* 52.083

AZ Mark DALLAM 1950

N 37* 01.994

W 086* 51.776

The AZ mark was in plain sight next to the road, I went by it twice yesterday and didn't even see it. But when I was looking for it, I spotted the mount from 50 foot away. Terra Vador's coords were right on.

 

Thanks for all the help, now I don't think I'll have nearly as much trouble finding triangulation stations.

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I still use GPS Trackmaker.

DGTV

 

You can add the distances and bearings into it send it to your GPS and go right to them.

 

I have found it to be one of the best tools yet.

 

I also keep a track log of all my activities with it.

Then you can see where you have been already.

And it also proves you were there for X amount of time.

Each leg will give you speed and distance of your travel.

That is just a few of the things you can do with it.

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Thanks again to everyone for the advice and information.

 

Since this station was pretty straightforward and was in good condition, I'd like to log it with NGS. How much detail do I need to go into, it hasn't been reported since 1952. Can I simply state that all markers are in good condition, mention a few geographical changes (i.e. the road is now blacktop) and give coords for the marks. (Mentioning they were measured with a handheld.)

 

I'd like to submit it and see how difficult/ easy it is to report BM's.

Edited by Airmapper
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Airmapper -

 

Dave Doyle (king of the NGS) once told a group of us NGS-reporting benchmark hunters that the NGS was primarily interested in knowing (1) whether or not a benchmark exists and, if so, (2) what condition it is in. Everything else beyond that is gravy.

 

Were I to report this recovery to the NGS, I would:

1. Indicate that the station, both reference marks and the AZ are in good condition (assuming that thyey are, of course).

2. I would provide the handheld coordinates for the AZ, but not for the station or for either of the RMs. (The main station is defined by ADJUSTED coordinates, and your handheld cannot improve on that if the station is in GOOD condition. The RMs are too close to the main station for handheld coordinates to be much relevant help in locating them. Someone searching for the AZ would however, benefit from knowing your handheld coordinates. In the recovery comments, I would include the comment "HANDHELD COORDINATES FOR THE AZIMUTH MARK ARE NXX-XX-XX.XX W0XX-XX-XX.XX". Remember to convert the coordinates to DD-MM-SS.SS for inclusion in the NGS recovery.

3. I would mention changes in the environment if the new info would help someone find the station and/or RMs and AZ in the future. For example, I may say "THE AZIMUTH MARK IS LOCATED XX.X FEET NORTHWEST OF THE CENTERLINE OF THE BEECHLAND-QUALITY ROAD WHICH IS NOW PAVED."

 

Of course, thoroughly familairize yourself with caseyb's FAQs at the NGS forum before proceeding.

 

Will

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It took me a while to get this ready, my computers been down and I just now got it ready.

 

This is a first draft, I thought I'd post it here before submitting, being my first one.

 

10-28-2005

 

Found Dallam 1950, all disks are in good condition and are legible. All disks appear to have held position well.

 

A few changes to the area include:

 

Sand Springs Methodist Church building is no longer standing, but the foundation corners are still present.

-

Beechland- Quality Road is now paved.

-

Reference Mark 2 is on the South side of Beechland- Quality Road, the Cemetery has now extended to both sides of the road making the description confusing.

 

Azimuth mark was found in good condition, it is in visible sight in a modern fencerow.

Azimuth Mark Coordinates taken with handheld GPS, averaged.

N    37*01'59.6"

W 086*51'46.6"

 

Well how'd I do?

Edited by Airmapper
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A 'distant' picture showing both the main mark and the corner of the foundation would be very good to include in the GC log.

 

One or two white witness posts are mentioned for the main station and its reference marks and another white witness post is mentioned for the AZ mark. What about those witness posts?

 

There are 2 ways to write a description:

1. identify changes

2. rewrite the whole thing

 

You could consider rewriting the whole thing since over 50 years have passed (the mark is the same age as me). Just copy and paste the old description and then edit it is one way to do it.

 

What if the church's foundation corners are removed tomorrow? Is there an additional way of locating the mark?

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It took me a while to get this ready, my computers been down and I just now got it ready.

 

This is a first draft, I thought I'd post it here before submitting, being my first one.

 

10-28-2005

 

Found Dallam 1950, all disks are in good condition and are legible. All disks appear to have held position well.

 

A few changes to the area include:

 

Sand Springs Methodist Church building is no longer standing, but the foundation corners are still present.

-

Beechland- Quality Road is now paved.

-

Reference Mark 2 is on the South side of Beechland- Quality Road, the Cemetery has now extended to both sides of the road making the description confusing.

 

Azimuth mark was found in good condition, it is in visible sight in a modern fencerow.

Azimuth Mark Coordinates taken with handheld GPS, averaged.

N    37*01'59.6"

W 086*51'46.6"

 

Well how'd I do?

 

I like the work you have done! You have tried to be very conscientious in your hunting and recovering. Here is just a comparison of how we in the Survey field might approach this given stations recovery info:

 

"Found Dallam 1950, all disks are in good condition and are legible. All disks appear to have held position well."

 

We might say instead:

 

All Caps: "STATION AND ALL RM'S FOUND IN GOOD CONDITION." You are submitting this info to the PID for DALLUM 1950, so the correct name will be assumed. Please try not to refer to the "seems" about positions as you could call position into question by saying so and you don't have the equipment needed to verify it. Just say you found them and they look good :-) It is really important to stick to what is and not what seems. If you found them and one looks like a lawn mower scuffed the disc and the center is no longer got the triangle or the arrow, what have you, you could say it looks poor. You could say why it looks poor too.

 

A few changes to the area include:

 

All Caps: "DESCRIPTION UPDATES WILL INCLUDE: or, TO FIND UPDATES WILL INCLUDE:

 

Sand Springs Methodist Church building is no longer standing, but the foundation corners are still present.

 

All Caps: CHURCH BLDG REMOVED, FOUNDATION CORNERS STILL EXTANT AND USABLE.

 

We have to be as brief and succinct as we can as there may be a lot we find needing to update, but there is only so much room we are allowed to use when updating. You get the idea... :-)

-

Beechland- Quality Road is now paved. Good! But can you treat this as an update to the "to reach"? Is the to reach still adequate? if so, good, but note that the said road has been paved and that the church building that will be looked for is torn down though the foundation still exists. A surveyor may be looking for a gravel road and a church during the to reach part. People tend to think in chunks. The to reach is a different chunk than the to find...

-

{{Reference Mark 2 is on the South side of Beechland- Quality Road, the Cemetery has now extended to both sides of the road}} Good! But this part: "making the description confusing". is not important, instead, can you add something that will add to the ability to find RM2? Can you reference it's location to something new yet permanent? can you make it less confusing? Something that will help? Just add that which adds value.

 

{{Azimuth mark was found in good condition, it is in visible sight in a modern fencerow.}} Good! But can you better define the type and style, or appearance of the fence? What does this fencerow seem to form the border of, and what directions is the fencerow running? Is it a galvanized chain link fence running 210 degrees true? Is it a split rail cedar fence running 100 Degrees true? Believe it or not, I am not sure what you mean by a modern fence... Sorry! Are you refering to the age of the fence? Will the fence still be modern in 50 years from today? Do we know what will be considered modern 80 years from now? Is the fenceline overgrown with brush or is it currently maintained? will it be maintained in 25 years from now? How many posts from the corner of the fence (which corner is important too) is the AZ mark closest to? True will imply to me that you did compensate for magnetic declination when you were there. In 100 years Declination will change some but if I observe this, true will still be true, then.

 

Could you check in and confirm the distances to the RM2 and AZ Mark and confirm them? Heck get RM 1 as well. This will remove any doubts cast by the 1952 survey.

 

{{Azimuth Mark Coordinates taken with handheld GPS, averaged.

N    37*01'59.6"

W 086*51'46.6"}}

 

This part is not necessary. This is a First Order Horizontal Survey Marker which in both cases was surveyed using a Tower 26 meters high. This was around 85.3 feet above ground. This is the highest optical accuracy possible and a hand held GPSr is not capable of bettering it. The best time to report coordinates is when you have found a Scaled Bench Mark. That always helps us find those easier because they are rarely accurately horizontally located.

 

Hope those pointers help you out, and by the way, Nice Job! You were quite thorough and mindful of what you wanted the description to have!

 

HTH,

 

Rob

Edited by evenfall
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