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m&h

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Posts posted by m&h

  1. The map mloser led us to has many coverage polygons, none of which are overlaid on the mark site. A little further digging turned up the Chief of Survey for PennDOT, who told us that the disk in question is in a database that he maintains, and which is not online. He kindly added that the elevation for this disk is 963.35’, and that its stamping is 06F-57-3006-7. Close to what we deduced from the picture, and we can see it now.

     

    Cheers,

  2. As you already know, this is a state department of transportation mark. It's hard to say how many thousands of these there are. Sometimes they have been set, or resurveyed, to the standards of accuracy required for inclusion in the NGS database, but much more often they have not.

     

    We've found quite a few of these in other states than Pennsylvania, and of course we log them in our private database, and sometimes we find a state database that includes them.

     

    If we were looking for this one, we'd be using its GPS coordinates to start with, if we had them.

     

    Good picture!

     

    Cheers,

  3. Hi--

     

    "Coords are: N 39* 55.7032,W 084* 73.8135."

     

    These don't work on our finding aids, because the longitude has a minutes value that exceeds 60. Some sort of typo, we imagine.

     

    We'll check back in case of a correction.

     

    Best,

    m&h

  4. We'd like to cast a vote against trying to excavate the underground mark, unless you can arrange to do so in the presence, or with the help, of a licensed professional. It's the very last mark for the point, so disturbing it is totally destructive of the point. Back in the day, a missing surface mark that couldn't be restored by the reference marks could be restored by carefully digging down to the underground mark, and then putting over the hole a device called a plumbing bench. This had legs that could be sturdily planted, like the legs of a tripod, and a plumb-bob hook in the horizontal part that could be slid around and locked in place with thumbscrews or the like. So the plumb bob was centered over the underground mark, the hook was locked in place, and the hole was very carefully filled (don't bump that bench!) to accommodate the new surface disk, whose position could be made exact by re-hanging the plumb bob. Such restoration is now a lot easier with instruments, but our guess is that it's rarely if ever done any more.

     

    Cheers,

  5. Jim,

     

    We're always very grateful for the work you do for us and the way you do it. Thanks again!

     

    As for AZCachemeister's question, it's us and them, apparently: On the one hand, we reported 9 recoveries to NGS in December. On the other hand, our 50 for the year is about sixteen down from the top, and in 2009 our 120 for the year was around twenty down from the top.

  6. We found SD0558, and discovered that, though we are about the fifth log, we may be the first actual finders (there are a couple of logs without photos). Get within sight of a witness post, and you may be in the right place . . .

  7. Every state sets large numbers of survey marks. Occasionally the accuracy with which they are set is up to the standards of the NGS, and the mark is submitted for addition to the National Spatial Reference System. Usually not. So Waymarking.com is about it for these, if the coordinates don't turn up anything. Good hunting.

  8. Ugh. sorry about that fill-page quote, which we did not intend.

    We came across the same thing with DL 2668, CAM F, just south of Anacortes. New mark. Our tentative conclusion is that the mark is actually a DB, mistyped as a Horizontal Control mark. Your case is a little more complicated by the relatively low order of the mark in either category.

     

    Cheers,

  9. On rare occasions we've come across Triangulation Stations with no Box Score. But this one goes a step further and lists only Scaled coordinates (with 3rd order vertical elevation).

     

    - I thought all tri stations were horizontal control? (Maybe I haven’t been paying close enough attention).

     

    - Also, would there be any way to find box score information for this?

     

     TR2743 ***********************************************************************
    TR2743  DESIGNATION -  DRAYTON ISLAND 2
    TR2743  PID         -  TR2743
    TR2743  STATE/COUNTY-  WA/WHATCOM
    TR2743  USGS QUAD   -  BIRCH POINT (1994)
    TR2743
    TR2743                         *CURRENT SURVEY CONTROL
    TR2743  ___________________________________________________________________
    TR2743* NAD 83(1986)-  48 58 55.     (N)    122 47 13.     (W)     SCALED    
    TR2743* NAVD 88     -         4.22   (+/-2cm)      13.8    (feet)  VERTCON   
    TR2743  ___________________________________________________________________
    TR2743  GEOID HEIGHT-         -21.19  (meters)                     GEOID09
    TR2743  VERT ORDER  -  THIRD ? (See Below)
    TR2743
    TR2743.The horizontal coordinates were scaled from a topographic map and have
    TR2743.an estimated accuracy of +/- 6 seconds.
    TR2743
    TR2743.The NAVD 88 height was computed by applying the VERTCON shift value to
    TR2743.the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.)
    TR2743.The vertical order pertains to the NGVD 29 superseded value.
    TR2743
    TR2743.The geoid height was determined by GEOID09.
    TR2743
    TR2743
    TR2743_U.S. NATIONAL GRID SPATIAL ADDRESS: 10UEV155254(NAD 83)
    TR2743_MARKER: DS = TRIANGULATION STATION DISK
    TR2743_SETTING: 7 = SET IN TOP OF CONCRETE MONUMENT
    TR2743_SP_SET: IN CONCRETE IN A CLAY TILE PIPE
    TR2743_STAMPING: DRAYTON ID 2 1939
    TR2743_MARK LOGO: CGS   
    TR2743_PROJECTION: FLUSH
    TR2743_MAGNETIC: N = NO MAGNETIC MATERIAL
    TR2743_STABILITY: C = MAY HOLD, BUT OF TYPE COMMONLY SUBJECT TO
    TR2743+STABILITY: SURFACE MOTION
    TR2743_SATELLITE: THE SITE LOCATION WAS REPORTED AS SUITABLE FOR
    TR2743+SATELLITE: SATELLITE OBSERVATIONS - August 02, 1984
    TR2743
    TR2743  HISTORY     - Date     Condition        Report By
    TR2743  HISTORY     - 1939     MONUMENTED       CGS
    

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