RISCWORLD 5/RISCWORLD_VOL5.iso/SOFTWARE/Issue5/LEYFIND.ZIP/LeyFind/!LeyFinder/!Help

Text File | 2005-01-02 | 13.0 KB | 293 lines

LeyFinder Martin Carradus Version 1.00 January 2005
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DISCLAIMER - AGREEMENT

Users of LeyFinder must accept this disclaimer of warranty:
"LeyFinder is supplied as is.  The author disclaims all
warranties, expressed or implied, including, without limitation,
the warranties of merchantability and of fitness for any purpose.
The author assumes no liability for damages, direct or conse-
quential, which may result from the use of LeyFinder."

LeyFinder is a "shareware program" and is provided at no charge
to the user for evaluation.  Feel free to share it with your
friends, but please do not give it away altered or as part of
another system.  The essence of "user-supported" software is to
provide personal computer users with quality software without
high prices, and yet to provide incentive for programmers to
continue to develop new products.  If you find this program
useful and find that you are using LeyFinder and continue to use
LeyFinder after a reasonable trial period, you must make a reg-
istration payment of £10 (UK) or $20 (US) to Martin Carradus.
The £10 (UK) or $20 (US) registration fee will license one copy for use
on any one computer at any one time.  You must treat this software just
like a book.  An example is that this software may be used by any
number of people and may be freely moved from one computer
location to another, so long as there is no possibility of it
being used at one location while it's being used at another.
Just as a book cannot be read by two different persons at the
same time.

Commercial users of LeyFinder must register and pay for their
copies of LeyFinder within 30 days of first use or their license
is withdrawn.  Site-License arrangements may be made by con-
tacting Martin Carradus.

Anyone distributing LeyFinder for any kind of remuneration must
first contact Martin Carradus at the address below for authorization.

You are encouraged to pass a copy of LeyFinder along to your
friends for evaluation.  Please encourage them to register their
copy if they find that they can use it.  All registered users
will receive a copy of the latest version of the LeyFinder
application.

Description:
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Finds straight lines of ancient sites given their grid references, the
minimum wanted in a line and the chosen 'accuracy' of the line. Plots
the sites and found lines on a 'map' of the chosen area. Map can be
saved to a file, both before and after plotting of lines.

NB This program is designed solely for use with grid references on grid
systems not extending over more than 600 miles (1,000 kilometres).
It is not designed for use with latitude and longitude and does not
employ any spherical trigonometry in its calculations.

Information needed by the program and Options offered:
------------------------------------------------------

The Two Algorithms:-
--------------------
The basic (Quick) algorithm goes through all pairs of sites, establishes
the line between them, then runs along it looking for other sites
on the line within the desired degree of accuracy. At the same time
all pairs of sites along the line are eliminated from further consid-
eration. This is done by keeping an internal look-up table which
records whether any particular pair has been considered or not before.

The elimination of pairs along the line is done without any regard
to the direction of the line between them. This would be correct if
all the points along the line lay exactly on it. However they usually don't
and the algorithm tends towards radiating lines because any crossing
lines tend to be suppressed. The second algorithm takes account of
crossing lines by only eliminating pairs along an established line if
the line between them lies sufficiently close in terms of its gradient
(angle of slope). The user supplies an angle in degrees within which
lines must lie to be eliminated. The first algorithm does find valid lines,
but tends to exaggerate the radial look of the final plot of the found lines.

The overall problem with both algorithms is that it is conceivable
that lines could exist where none of the points lie exactly on them.
Both algorithms require that at least two points lie on it within the
degree of accuracy of the swathe cut by the line.

Fixed Scan or Random Scan:-
---------------------------
A fixed scan goes through the pairs of sites in a systematic order
i.e. site 1 with site 2, site 1 with site 3, site 1 with site 4 etc.

A random scan goes through the pairs in a non-systematic order
e.g. site 6 with site 9, site 2 with site 7, site 4 with site 6 etc.
, but in such a way that all pairs are considered.

Fixed Start or Random Start:

A fixed start always starts with the same pair i.e. site 1 with site 2
A random start chooses a different pair each time the program is run.

Hence a fixed start guarantees the same result every time, but a
random start will tend to produce a different result every time.

In order of 'randomness' (from least to most), there is:

1.Fixed Scan, Fixed Start.
2.Fixed Scan, Random Start.
3.Random Scan, Fixed Start.
4.Random Scan, Random Start.

Creation of New File:

Offers the user the option of creating a file of grid references
and immediately analysing it for ley lines. A new file may be
created either internally or externally. An existing file can be
appended to, to add additional sites. A record number is supplied
to which you supply an easting, northing and site name. All three
must be supplied, then click on the 'Next' button to move onto
the next record. Click on the 'Close' button to close and end the
file.

Otherwise program asks for:-

Name of file of map co-ordinates:

This is the file containing the co-ordinates of the sites. The format
of the file is a set of lines of values, each line consisting of a
site number (not necessarily in any order), followed by the easting,
followed by the northing, followed by a string of up to 30 characters.
(The string being a name associated with the site.) These values
are separated by commas. The easting and northing should be whole
numbers and the string starts with a capital 'X' or small 'x' for an
highlighted site or anything else for a un-highlighted site. The string can
simply only be a single character if there is no name associated with the
site. Names need not be unique. File should end with a new line.
This file may also be created by using something like Edit or DeskEdit.
It is checked as it is read in an elementary way. There should be at least
ten sites in the file, but not more than 1000. Estimated time for processing
the full 1000 sites is around two and a half hours with my StrongArm and
RISCOS 4, less for faster chips.


Automatic Scaling:

Will adjust the scaling to fit in all the sites on the screen.

Will also adjust the scaling so that it is the same east-west as
north-south. Otherwise usually unequal scaling in the two directions.

Manual Scaling:

The minimum and maximum co-ordinates east-west and north-south are
chosen by the user, so that any area of interest can be focused on.

Grid Lines:

These are horizontal and vertical lines that indicate the change of
grid reference across the screen. If you choose this option a suitable
grid interval is suggested, which may be over-ridden. Program will not
allow too many grid lines. Grid lines do not erase the supplied site points.

Sites in Line:

One of the two most important parameters. It is the number of sites
found in a line below which the line will be rejected. Too small and
the map will fill with lines. Too large and no lines will be found. It
has been found that 15 is a reasonable amount to start with for about
200 sites.

Width of Line:

The second most important parameter. This is the number of pixels across
the line within which a site will be considered to lie.
Can be fractional. This is across both sides, so if a value
of 1.5 is chosen, the swathe cut by the line will extend by 0.75 pixels on
either side. The screen mode within which this program operates means
that the pixel (elementary part of image) is twice as high as wide.
Consequently the width of the swathe is adjusted so that when the line
is near horizontal it is wider than when the line is near vertical. It
is suspected that near horizontal lines will tend to be detected more
easily than those near vertical. Points that lie too close together on
the screen will be rejected, since the line through them cannot be
determined accurately within the confines of the co-ordinates
supplied. If the width is too small, no lines may be found. If the
width is too large, many inaccurate lines may be found. A starting
value of one pixel is suggested.

Bell Sound:

Single normal bell sound on each discovery and/or high-pitched bell
sound on completion.

Titles:

An option of having a title after the plotting of points and before
the plotting of lines and/or one after the plotting of lines.
Up to 72 characters including embedded spaces. Neither grid nor title
before will erase the points on the screen as the points are plotted
last.

ScreenSave:

Option of saving the screen to a Acorn Sprite file, either after plotting
of points or after plotting of lines. No recovery is offered if the file
names the user supplies are incorrect in any way, but a message
will indicate the ScreenSave failure. A 'Saveas' panel appears, where
you may drag the file icon with the mouse to a suitable directory, if required.

Screen Display:

Points, Grid Lines and Title (if chosen). Chosen points highlighted in
red. Rest in black. Background white. Percentage through process shown
by an hourglass mouse pointer. On the title bar the actual number of lines
found so far followed by absolute maximum found in all lines.
Holding down any key at at any time will halt the process, otherwise the
completion of process, or a maximum of 1000 lines being found will
also halt the process.

On Completion:

The found lines are plotted. Those of maximum occupancy are plotted in
magenta, the rest in blue. If there are none or a maximum of 1000 has
been found, a message is displayed. The screen is saved, if this
option was chosen. Close the window to end the program. From the bar icon
menu, click on 'Reset' to repeat the process, possibly with a new file, or an old
one with new run-time parameters.

Warning:

This program merely takes the donkey-work out of finding ley lines
and the accuracy of the results are not guaranteed. It does not
substitute for actual investigation on the ground and map. Britain, in
particular is virtually littered with ancient sites, so almost
anything will fit. Straight lines of telephone boxes have been found
in the past! The algorithm (method) used seems to bias in favour of
lines radiating out of certain sites with the fixed scan. The random
scan was introduced in an attempt to get rid of this bias. It is hoped
to give the likelihood that the line could not have occurred entirely
by chance, plus more statistics on the found lines in future versions.

Comments, queries, curses, and praise to:-

         Martin Carradus,
         Leaf Mindcraft,
         c/o 27 Wells Road,
         ILKLEY,
         West Yorkshire.
         LS29 9JE.
         U.K.

Enclose s.a.e. if you want a reply.

File 'Stones' within this application contains eight figure grid
references of some of the cup-and-ring marked stones on Rombalds Moor
(Ilkley Moor). Stones thought to date from 1500-1800 B.C. and no one
is totally sure of the significance of the markings or even exact
antiquity. Such markings are not entirely unique within this area or
within Britain (know of others in Northumberland and Galloway). Even
eight figure grid references only reduce the inaccuracy to a ten
metre square, which is about the floor area of an average house, so
not that accurate considering the size of the stones and the markings.
Would probably have to use satellite navigation to get any degree of
accuracy and I don't know how these grid references were worked out
in the first place. Grid references obtained from:

  "The Carved Rocks On Rombalds Moor" West Yorkshire Metropolitan
  County Council 1986 ISBN 0 86181 008 2. Thought now to be out of
  print.

Not all those available were put in the file.

There is now (2005) a more complete listing of the cup-and-ring marked rocks
mentioned above in 'Prehistoric Rock Art of the West Riding'  by the 'West
Yorkshire Archaeology Service', editors K.J.S. Boughey and E.A. Vickerman,
(2003) ISBN 1 870453 32 8, ISSN 0959-3500.

Information on those markings in Galloway can be obtained from:

  "The Prehistoric Rock Art of Galloway and the Isle of Man"

  Ronald W.B.Morris Blandford Press 1979

  HardCover: ISBN 0 7137 0974 X
  PaperBack: ISBN 0 7137 0975 8  Might also be difficult to get - I
  found it in a remainder book shop.

The files 'Test' and 'Test2' are test sets of grid references to demonstrate
that this program really works! For 'Test' choose an occupancy of 10 and
a width of 1.0. For 'Test2' choose an occupancy of 5 and a width of 10.0.
Both files buried inside this application. Use 'Internal' to get them!

Good Luck in your investigations, but don't come to wild conclusions!