SIY2.TXT    Write a Land Description from a Map               22


                            Chapter 2


               Write a Land Description from a Map


For this chapter you will need:

a) Silva Ranger type 15 compass, available for $43 + $5
shipping & handling from CAVE Inc, 1/2 Fast Road, Ritner, KY
42639.  606/376-3137.  If you do not have a Silva Ranger compass,
then you may substitute a circular protractor and a ruler.  You
could even make do with a schoolchild's protractor and ruler, but
you won't like it.

b) These instructions,

c) Pencil & note paper,

d) The maps which you plotted in Chapter 1 or 1_C.

You will NOT need:

a) Any land,

b) Any land description,

c) Any assistants,

d) Nor to leave the comfort and safety of your kitchen.

e) You don't even need this computer, except to make a printout
so that these instructions can be doodled with a pencil.

Label your note paper "Data measured from Map 1".

Make column headings, "TO FROM COMPASS TAPE COMMENTS".

Get out the map which you made from the data of Table 1.

Station 0 is the starting point.  On the first line write "0" for
station TO, "0" for station FROM, 0 for the COMPASS direction,
and 0 for the TAPE distance.  Now you have started somewhere.




 SIY2.TXT    Write a Land Description from a Map              23


Onwards.  TO 1, FROM 0.  Lay your compass on the map next to
station 0.  Turn your compass so that the mirror points in the
direction of travel.  Slide the compass so that the edge of the
compass base aligns with the line TO 1, FROM 0.  Now turn the
compass dial so that the red and black arrow points north on the
map and the black lines inside of the dial align with the
north-south lines on the map.  Remove the compass and read the
COMPASS direction under the index blob.  Record this number in
your notes.

To measure the TAPE distance, use the ruler on the base of your
compass.  Remember, this ruler is graduated in twentieths of an
inch, not sixteenths.

Fill out your table of data.  At each station, record the station
TO, the station FROM, the COMPASS direction, and the TAPE
distance.  Now compare this table with Table 1.  They should be
the same.

How close is close enuf?  For now, 5 degrees and 5 hundredths of
an inch.  For serious work you can be accurate to 1 degree and 1
hundredth.

Any boundary on a map can be described as a land description by
this method.

1} Start someplace.

2} Then measure the direction and distance to the next point.

3} Repeat step 2 until you have your land description.

Any point on the map, such as the location of a building, well,
or cave could be described in this way.  Draw a line TO the point
FROM a point which you have already located.  Measure the
direction and distance.  The station FROM need not be THE
previous station.  It need be only _A_ previous station.  Be sure
to keep track of the station FROM when you write your land
description.

Now label another table.  The name of this table is "Data
measured backwards from Map 1".  Write the standard column
headings, "TO FROM COMPASS TAPE COMMENTS".  Add another column,
"compass backwards".



 SIY2.TXT    Write a Land Description from a Map              24


Start at station 4.  TO 3, FROM 4.  Measure and record the
compass and tape the same way as you did before.  In addition, at
each station take another compass direction reading with the red
and black arrow pointing backwards.  Pointing south on your map.
Record this direction under compass backwards.

Compare the land description going forwards with the one going
backwards.  Notice that you have the same compass and tape (or
close enuf) going in either direction around the map.  They are
in different places, to be sure.

The value of "compass backwards" can be calculated.  Simply add
180 to, or subtract 180 from, the compass reading going in the
normal direction.  Take the choice which gives the answer between
0 and 360 degrees.

Play around with this until you are convinced that you can
translate map into land description, and land description into
map.  Forwards and backwards.  Fluently.  And when you get
confused again, draw yourself pictures until you are unconfused.

No magic.  Magic is for such as magicians and politicians.  It
will get a surveyor or a scientist into BIG trouble.  Don't.

Copyright (c)1995 by David Perry Beiter

If you have any questions, problems, or comments, write or call
me.  Dave Beiter, CAVE Inc, 1/2 Fast Road, Ritner KY 42639.
606/376-3137.
MCI Mail: 635-1762
byter@mcimail.com
X.400: c=US;a=MCI;s=BEITER;d=id=6351762
CIS: >MCIMAIL 635-1762 (be sure to include your name in the text)