Agriculture Reference
In-Depth Information
Consider the information included in Figure 6.2. A grid is projected
on the ground, shown as an x/y-axis. This information is useful in the
sense that it would be possible to retrace the location of the grid on the
basis of a known reference system by which the grid coordinates are a
part of such as one established by the United State Geological Survey
or a state coordinate system. The grid provides a means of establishing
horizontal control. Also in the photograph is a vertical line that rep-
resents elevation control. So, if there was an established horizontal and
vertical referencing system in the vicinity (such as a city) that one could
research (to find the control systems), it would be possible to reestablish
the grid system—in this example, to locate the person asking where he/
she is on the subject property, and the elevation where the person is
standing.
Maps are drawn for many purposes. In the case of the map in Fig-
ure 6.4, the purpose was simply to provide directions using roads, land-
marks, and physical features to guide a traveler to a destination. The
map in Figure 6.4 represents one of the most common types of two-di-
mensional maps used to convey information and accomplish a particu-
lar purpose. The map was hand-drawn providing directions to Chum's
Fishing Camp. Obviously it was drawn by hand, perhaps on a handy
piece of scrap paper or napkin, with
little concern about scale and pro-
portional accuracy. To be useful, the
hand-drawn map needed to be accu-
rate in arranging the important phys-
ical features of the immediate area
(roads, trees, building, and bridge).
Mileage indicating the distance from
the Highway 92 turn-off to Dalton
Road is the only numerical reference
provided. The person who drew the
map included only the most relevant
physical information, north not being
considered important and probably
of little direct use to the traveler.
Chum's
Fishing
Camp
Colfox Ln
Toyaco
Gas
Figure 6.4
Directions sketched on a piece of paper for finding
Chum's Fishing Camp
