Navigating by Maps - A Primer
Reprinted with permission from Mother Earth News
by Larry William Koontz


Yes Folk's ,the government sometimes does work for the little guy..and
many of us don't realize just how helpfull Uncle Sam can be,especially
to  people who need information about land. Wether you're looking at a
tract you'd like to buy or evaluating different  ways  of  using  some
acres  you  already  own,  government-issued maps can be invaluable in
helping you make informed decisions.

Of course,anyone who's  examining  a  prospective  tract  of  land  or
planning  a new project on his or her spread is bound to have a lot of
questions. Such an individual will perhaps want to how the acreage was
used in the past...or what minerals are present in the soil  and  what
crops  it  will  support  successfully... or the location of favorable
sites  for  a  well  or  a  solar  dwelling....or  the  areas  average
rainfall,temparature  range,  and  frost  dates. Well ,those (and many
others) vital statistics can be easily obtained at very  low  cost  --
sometimes  even  free  of charge--from good old Uncle Sam himself. All
you have to do is  learn  how  to  use  various  technical  maps  that
government offices can provide.

A LONG-DISTANCE LAND SEARCH

You may be better able to use maps to answer your own questions if you
know  how  I took advantage of this form of low cost assistance. about
two years ago, my wife and two children and I decided to  buy  several
acres  in  Tennessee...and  to do this while living in Florida! As you
might expect,purchasing land in one state while  residing  in  another
pre-  sents  some  unique  problems...so  we  were  glad to enlist the
government's service.

After the family returned to Florida following a somewhat hectic  four
day  sweep  thruogh  selected  areas  of  our  future  home  state, we
THOUGHTwe'd foung our  dreamed-of  piece  of  Mother  Earth....but  we
simply  weren't  sure. Doubts about the acreage kept popping up in our
minds,and we felt that our short tour of the parcel hadn't provided us
with all the facts we should know before making a decision.

Our first step,then, was  to  write  for  a  map  of  the  whole  area
surrounding  area  of the property-to-be. (since we had passed thruogh
the cuonty seat on a week-end,we hadn't been able to get one  at  that
time)  Road  maps are usually distributed free by county gov'ts,or you
might be able to secure one-for a small  charge-from  the  Chamber  of
Commerce  serving  the  area in question. Then we went on to acquire a
complete set of topographic ,geologic,and soil survey  maps  for  that
particular  tract.  Eventually  -  after  we  learned  how  to read and
interpret all  the  documents  we  received,  we  gained  an  intimate
knowledge  of  the  acreage  we  were considering,and by the time were
turned to Tennessee two months later to close the land sale,  we  knew
our spread inside and out!

MAP BASIC

You  don't  have  to be a trained cartographer to decipher topographic
and geologic maps. In fact, you need only a few  simple  skills...most
of  which  you  probably  learned  in  your 6th grade geography class.
North,of course is always at the  top  of  the  map  as  you  hold  it
straight   in   front   of   you,with  the  other  directions  at  the
corresponding positions on the sheet: south to the bottom, east to the
right, and west to the left.

The SCALE-which is usually noted in  the  margin-tells  you  how  many
miles(or feet) are represented by each inch on the map. There's also a
LEGEND  that  explains  the symbols, numbers,or color shadings used on
the diagram. It's wise,too,to look for the date on which the  map  was
drawn   and/or  revised...since  streambeds  do  shift,and  roads  and
buildings come and go.

In  short,  all  the  information  you'll  need will be right there in
print. You'll just have to use your imagination to translate that  one
dimensional picture into an image of the actual landscape.

Now  that SOUNDS easy, I know,and it will seem to be so..... UNTIL you
unfold a topographic map for the first time. Believe it or not,though,
that confusing swirl of lines, blotches,dots and numbers  (which  will
tend  to  bewilder  you  at first) can actually convey a great deal of
important information to any future or present land  owner  who  knows
how to read it.

TOPOGRAPHIC MAPS

A  topographic map is no more (or less!) than an accurate and detailed
representation of  a  specific  portion  of  the  earth's  surface.  It
indicates  streams and springs,lakes,roads and trails,buildings,wooded
areas(these are shown in green),and-most important of all - the actual
contour of the land. With its distinctive curving  lines,  the  "topo"
map  (as  commonly  called)  manages  to  produce a three- dimensional
picture on a flat surface. To understand this, think of a  topographic
layout  as  a  view  from above... looking straight down on a piece of
property's peaks, valleys,  and  slops.  The  rise  and  fall  of  the
landscape   is   represented   by   the   map's   curving  lines.  (in
fact,cartographers commonly draw or update these maps with the help of
high-resolution aerial phothgraphs... but only do so AFTER  making  or
consulting a detailed ground survey).

The  topographic contour lines portray elevation intervals of 10 or 20
feet,so the map reader can figure not only how high the land  is,  but
also  how  gradually-or  steeply  it sloops. For example, in fig.#1 (a
typical ridge) the  wide  spacing  of  the  lines  on  the  south  and
southeast  faces  ofthe  land mass indicate a gentle downward incline.
The contour lines on the East side,however,are so close together  that
the map reader can deduce the presence of a cliff.. ..and fig#2, which
is a ground-level view of the same piece of land,proves the point.

Once  you have a clear understanding of how to read a topo map,you can
learn lots of usefull facts about your land. The information can  help
you  decide  where to erect buildings and plant crops.......by showing
each  prospective  site's   steepness,   directional   exposure,erosion
patterns  , and soil drainage.It's best to use a "7-1/2 minute series"
map, which will provide the greatest detail among those types commonly
available. (the scale of such a drawing  is  1:24,000,  meaning  every
inch on the map equals 24,000 surface inches or 2,000 feet)

You can usually order a topo map from the Division of Geology  in  the
state  where your acreage is located.. ... but you may have to request
an index first,to help you figure out exactly which sectional map  (or
maps)  will  cover  your  land.  We  simply wrote to the state capitol
building in Nashville,Tenn and recieved an  index  of  topo  maps  for
$.25. The sized topo chart we ordered later only cost us $1.25.

SOIL SURVEY MAPS

After  you've become familiar with the lay of the land,you'll probably
want to learn something about the composition  of  its  earth....  and
thats  when  a  soil survey map can come in very handy. Offices of the
USDA's Soil Conservation Service are located in most County Seats  (as
well  as,  sometimes  in large towns) and the folks there will provide
you with information on the type of soil that's found on your  acrage.
In  some  cases, you can simply write to the office and recieve a free
information packet (as we did),  but  many  states  haven't  completed
their  surveying  yet.  If  that's the case,you'll have to stop by the
building to look at preliminary maps. You might also find a  reference
copy of the soil survey in the public library.

The  package  we  received  contained  comprehensive  set of four maps
covering every quadrant of the particular county we were interested in
PLUS a book that explained the symbols used  and  described  different
soil  varieties  found  in the region. Most soil survey maps are about
32"X 38", and they look something like topo maps (in fact,soil  survey
marking  s  are  sometimes  printed  right  on  top  of the same aerial
photographs used when making topo maps).  Instead  of  contour  lines,
however,  an  "earth  map"  shows  the irregular outlines of each soil
group. The copies we received further differentiated among the various
types by using a system of color coding. Each soil  "family"  is  also
identified by its own letter designation and examined in detail in the
booklet accompanying the map. By consulting both refrences,then you'll
be  able  to  find  out  how  the  soil  was formed, what nutrients it
contains, what its physical characteristics are, and --- probably most
inportant for  your  purpose  ---  what  crops  it's  best  suited  to
support... Along with any special cultivation requirements it may have
and  climatic  data for the area. In addition,you can learn what trees
are likely to be  found  on  your  land,and  your  soil  surveys  will
actually tell you what agricultural crops have been grown there in the
past!

GEOLOGIC MAPS

If you plan to develop any water sources or build with native stone on
your  land,  a  geologic  map can be an invaluable tool. The fact that
such a chart can usually be had for just a dollar or two  makes  it  a
wise  investment.  The  geologic  map  uses  as its base a topographic
drawing,complete with contour lines  and  elevation  markings(although
the  colors  are  usually  omitted)  plus a system of dotted lines and
letter symbols to represent the rock formations in the area.  It  will
also indicate any mineral deposits that might be hiding underground.

Before  you  even begin to search for a likely well site,you can use a
geologic map of your land to  locate  porous  rock  formation-such  as
sandstone  or  limestone- that might hold precious water. You may also
want to know what kind of stone you might expect to find that could be
used as building material.

Geologic maps  are  available  through  the  Geologic  Survey  of  most
states.  We  contacted the Geologic Office in Nashville,and found that
we could order a map of the area we were interested in for only $.25

A FANTASY COME TRUE

Although some folks might consider it  a  real  burden  to  study  and
interpret the specialized maps I've mentioned here, we found it really
easy--  and rather exciting -- to familiarize ourselves with our piece
of land this way. (and it may be the only way to do it,  if  you  live
too  far  away from the acreage to make a firsthand inspection trips).
Further  more,  pouring  over  a  collection  of  strange,   seemingly
indecipherable  maps  can  be  sort  of like visiting your own fantasy
land... Except that when you finally DO get a chance to walk the turf,
your "on-paper" version will be transformed into an earthy reality!

