; This was identical to the marblesteps-leckfell-gps-kdixon-2012.file in NC3-MarbleStepsAndLeckFell/survexdata/surface but now I've removed the gps points that aren't in Ease Gill ; so only the Ease Gill gps points are in this file and it is renamed - Becka May 2026 ; Cave: 3 Counties Geodetic GPS Survey ; Surveyors: Kevin Dixon/Tim Allen/Meg Stark/Ray Duffy(24 March only) ; Dates: 26 Feb 2012, 11 Mar 2012, 24 Mar 2012, 08 Apr 2012, 22 July 2012 ; Instruments: Leica Geosystems SR530 GPS, KD Suunto Prism Compass, Suunto Clino, Disto A3 and Disto D2 ; SVX File: Created 25 April 2012 by K.Dixon, updated 23 August 2012 ; Geodetic L1/L2 GPS post-processed using APPS at Jet Propulsion Laboratory, California to determine ITRF2008 Datum co-ords ; ITRF2008 co-ordinates determined for five OS GPS regional stations AMBE, BLAP, GIGG, LEED, RICM using same method ; 7 parameter transformation determined from ITRF2008 to ETRS89 for above five OS stations and applied to new 3C stations ; ETRS89 co-ordinates for 3C stations converted using online OS OSTN02 and OSGM02 models to determine OSGB36 and OSDN co-ords ; Position sigmas as determined by JPL, they do not include any uncertainties from the OS model transformations ; OS state that OSTN02 which determines OSGB36 easting and northing is error free ; OS further state that OSGM02 which determines the elevation has a standard error of 0.02m ; OSGB36 co-ordinates are for the OS 100km square SD *begin easegill-gps-kdixon-2012 ; was threecountiesgpskdixon2012 but Becka renamed as reorganising files May 2026 ; old name was 3cgps, BL updated to match the meaningful filename *date 2012.04.01 *export 009 ;Shuttleworth, top of radio location plastic pipe *export 011 ;Top Sink, RRCPC tag on scaffold *export 013 ;County Pot, left P hanger for metal cover *export 018 ;Leck Beck Head divers line tie point to root *export 020 ;Lancaster Pot, centre of central square hole in manhole cover *export 025 ;Bull Pot of the Witches, top corner of angle iron stake at stile *export 3C12 ;Aygill Caverns, original shallow drill hole survey marker above entrance ; known magnetic azimuth of 328.0 at Bull Pot Farm ; observed compass bearing of 328.0 ; therefore zero magnetic error ; magnetic north 02 degrees 14 minutes west of grid north as per British Geological Survey online calculator for July 2012 ; therefore zero correction term for survex is +2.23 degrees ;commented out by Simon Cornhill 2019.04.27 as it is superseded by *declination auto in leckfell.svx ;*calibrate compass +2.23 ; below are the fixed gps points collected in 2012 by Kevin Dixon et al in OS coordinates all sheet SD eg 3C01 is gps location for Lost Johns and rounding to integers it is "SD 67073 78633 354" ; *fix 3C01 67072.998 78633.040 353.7130 ;sigE 0.0253m, sigN 0.0427m, sigElev 0.041m ; *fix 005 66627.330 79065.580 327.5720 ;sigE 0.0141m, sigN 0.0291m, sigElev 0.021m *fix 3C03 66206.404 79776.565 279.4430 ;sigE 0.0148m, sigN 0.0464m, sigElev 0.037m ; *fix 3C04 66672.594 78314.807 315.3880 ;sigE 0.0187m, sigN 0.0266m, sigElev 0.037m ; *fix 3C05 66777.713 79158.695 333.6140 ;sigE 0.0219m, sigN 0.0122m, sigElev 0.027m *fix 3C06 68045.543 81098.638 342.6550 ;sigE 0.0132m, sigN 0.0238m, sigElev 0.020m *fix 012 67541.216 80563.308 314.3970 ;sigE 0.0160m, sigN 0.0634m, sigElev 0.078m *fix 014 65950.455 79975.28 215.2930 ;sigE 0.0115m, sigN 0.0235m, sigElev 0.030m *fix 3C09 66400.302 80715.594 294.7600 ;sigE 0.0190m, sigN 0.0163m, sigElev 0.050m *fix 025 66233.215 81301.541 294.3610 ;sigE 0.0137m, sigN 0.0545m, sigElev 0.024m *fix 026 66351.986 81827.754 297.0560 ;sigE 0.0156m, sigN 0.0280m, sigElev 0.038m ; *fix 027 68226.458 76851.614 397.7010 ;sigE 0.0154m, sigN 0.0190m, sigElev 0.024m ; *fix 029 68584.045 76985.121 401.2260 ;sigE 0.0141m, sigN 0.0263m, sigElev 0.028m ; *fix 032 67101.303 77807.68 373.3070 ;sigE 0.0141m, sigN 0.0266m, sigElev 0.030m ; *fix 3C16 67365.21 77338.954 387.7230 ;sigE 0.0216m, sigN 0.0953m, sigElev 0.117m *FLAGS surface ; below are the surface legs to connect each gps-fix to a known station in the underground survey (ideally something like a fixed tag) ; Shuttleworth Pot 11 Mar 2012 3C03 007 6.272 106.0 +05.0 ;3C03 is s/s bolt+washer in bedrock, washer stamped SHUTTLEWORTH 3C03, 007 is top of west scaffold clamp 3C03 008 6.905 107.0 +05.0 ;008 is top of east scaffold clamp 3C03 009 5.511 069.0 +06.0 ;009 is top of plastic pipe radio fix marker ; Top Sink 24 Mar 2012 3C06 011 0.721 169.0 +59.0 ;3C06 is s/s bolt+washer in top of bedrock in entrance, washer stamped TOP SINK 3C06 ; 011 is RRCPC tag on scaffold ; County Pot 24 Mar 2012 012 3C07 12.171 312.0 +04.0 ;012 is base of GPS antenna, 3C07 is s/s bolt+washer in wall to right of entrance, washer stamped COUNTY POT 3C07 3C07 013 0.905 243.0 -36.5 ;013 is left (looking at wall) P hanger used for manhole cover, entrance survey point for County ; Leck Beck Head 24 Mar 2012 014 3C08 4.925 233.0 -12.5 ;014 is s/s bolt in bedrock, 3C08 is s/s bolt+ washer in bedrock, washer stamped LECK BECK HEAD 3C08 014 015 1.227 - UP ;015 is base of GPS antenna 015 016 10.306 344.0 +00.0 ;016 is small boulder on grassy ridge 016 017 11.250 331.0 -16.0 ;017 is small boulder in dry bit of streambed 017 018 9.078 338.0 +03.0 ;018 is where dive line is tied to tree root 018 019 1.030 - DOWN ;019 is water surface level at Leck Beck Head ; note 3C08 is very close to RRCPC tag on boulder on ridge ; Lancaster Hole 24 Mar 2012 3C09 020 2.650 059.5 -16.0 ;3C09 is s/s bolt+washer set in large rock to south west of entrance, washer stamped LANCASTER HOLE 3C09 ; 020 is centre of square hole in centre of manhole cover ; Bull Pot of the Witches 31 Mar 2012 025 3C11 8.219 304.0 -05.5 ;025 is top corner of angle iron stake near stile, this is the angle iron at start of BPOTW cave survey ; 3C11 is s/s bolt+washer in bedrock near memorial plaque, washer stamped BULL POT WITCHES 3C11 ; Aygill Caverns 31 Mar 2012 026 3C12 7.768 343.5 -16.0 ;026 is base of GPS antenna, 3C12 is s/s bolt+washer in bedrock above entrance ; 3C12 was placed exactly in the shallow drill hole used as previous survey reference *end easegill-gps-kdixon-2012