; Dow Cave - Providence Pot system, including Dowbergill Passage

; Created 27/10/2015 by Patrick Warren (PBW) from an original by Steve Warren

; Surveyed 1982 (Dow Cave) -- 2015 (Dowbergill upstream of 800 yds chamber)

; The *.svx files here have unix-style line endings so on Windows you
; might have to use something like Notepad++ to look at them.

; Historically Providence Pot was classed as from the entrance to Stalagmite
; Corner, and the rest was classed as Dowbergill Passage (or Dowber Gill
; Passage), part of Dow Cave -- N. Brindle, CPC Journal 2(1), 4-9 (1955).
; The usage here 'Dowbergill Passage' follows Northern Caves vol 1 (1972-9).
; In terms of the survey data, Dowbergill Passage splits naturally at 800 yds
; chamber, where the WRPC re-survey ended in 2004.
 
; Magnetic declinations in individual files were originally calculated
; using the International Geomagnetic Reference Field (IGRF) model,
; with the online NOAA magnetic declination calculator, for the
; location (WGS84) 54.14929 N, 2.04008 W corresponding to SD 97480
; 72608 (Dowbergill Bridge, just above Kettlewell).  All these
; declinations are now commented out, as this method is deprecated in
; favour of using the *declination auto command below.  However it has
; been verified that both methods generate the exact same reduced
; survey data.

; People involved (in alphabetical order):
; Steve Barwick, Howard Beck, Simon Beck, David Bradley, Andy Cole,
; Peter Lamb, Becka Lawson, Shawn McMinn, Dave Morris, Russel Myers,
; Dennis Round, Gareth Sewell (Sweeney), Carmen Smith, Patrick Warren,
; Steve Warren, Edward Whitaker, Peter Whitaker.

; Clubs involved (in alphabetical order):
; Craven Pothole Club (CPC)
; Red Rose Cave and Pothole Club (RRCPC)
; White Rose Pothole Club (WRPC)

; Please feel free to re-use this cave survey data as you wish
; but please attribute to the caving clubs involved along the lines:
; "Based on cave survey data collected 1982-2015, CPC, WRCPC, RRCPC"

; For reference you can cite P. B. Warren, "The Dow Cave – Providence
; Pot Resurvey Project", CPC Record 122, 11-15 (2016).

; A version of this article can also be found on my website at:
; https://sites.google.com/site/patrickbwarren/caving/dow-cave) 

; Input CRS *fixes are NGR references, relative to the SW corner of
; the Ordnance Survey SD grid square, ie SD 000 000.

; If the output CRS is EPSG:7405 this is the British National Grid +
; ODN heights, and is equivalent to full numeric NGR references.

*cs OSGB:SD ; co-ordinates are 10-figure grid refs prefaced by SD

*cs out EPSG:7405 ; output is 12-figure OSGB36 + ODN height
;*cs out EPSG:27700 ; OSGB36 without ODN height
;*cs out UTM30N ; WGS84 UTM zone 30N
;*cs out EPSG:32630 ; WGS84 UTM zone 30N
;*cs out EPSG:25830 ; ETRS89 UTM zone 30N (E, N)
; DO NOT USE *cs out EPSG:3042 ; ETRS89 UTM zone 30N (N, E)

; Mag dec calculated for SD 97480 72608 alt 225m
; Dowbergill Bridge, just above Kettlewell

*declination auto 97480 72608 225

; Note that this should come _after_ the *cs and *cs out in order that
; survex knows which input CRS is being used to define the location,
; and which output CRS should be used to calculate the grid
; convergence (difference between grid north and true north).  For
; some output CRS such as EPSG:3042 (ETRS89 UTM zone 30N) the data
; interchange order is the 'wrong way around', ie (northing, easting)
; rather than the more usual (easting, northing).  Currently this has
; the unfortunate effect of throwing the grid convergence calculation
; out by 90 degrees, thus completely screwing up the calculations.
; Thus such CRS should be avoided for the time being.  As long as one
; uses *cs out UTM30N for WGS84 UTM zone 30N or *cs out EPSG:25830 for
; ETRS89 UTM zone 30N, one does not encounter this problem.

*title DowCaveAndProvidencePot

*begin DowCaveAndProvidencePot

*include DowCave/DowCave
*include DowbergillPassage/Dowbergill1
*include DowbergillPassage/Dowbergill2
*include ProvidencePot/ProvidencePot

*equate DowCave.dow2.31 Dowbergill1.dgp1.1
*equate Dowbergill1.dgp5.16 Dowbergill2.dgp6.46
*equate Dowbergill2.dgp7.1 ProvidencePot.PPot6.15

*flags surface
*include HagDyke ; surface feature -- building
*flags not surface

*end DowCaveAndProvidencePot