Geography Reference
In-Depth Information
bushes, no matter how large) and where a tree is. For example, these three
options for surveying the location of trees could be considered:
The tree is located at the center of its trunk at breast height.
•
The tree is the located at the northern-most point of the stem, not
including surface roots.
•
The tree is located at the center of its canopy, that is, the maximum
reach of its branches and leaves.
•
Depending on our purpose and how we want to geographically and car-
tographically represent the tree, one of these three approaches or perhaps a
different approach would be used. If we are conducting an environmental
analysis, knowing tree locations with an accuracy of 1-2 feet or even meters
may be sufficient. If we need to be more accurate, as accurate as a fraction of
an inch or a few centimeters, we need to rely on the help and services of an
expert surveyor, or a geodesist as they are also called.
The discipline of surveying and geodesy specifies methods, techniques,
and procedures when high accuracy is required for legal, building, or other
purposes. Surveyors are often called upon to meet legal requirements, but
they could also be to satisfy our desire to know as accurately as possible
where things are.
GPS is commonly used for recording locations for a variety of applica-
tions. It usually works less well in forests and where there are other obstruc-
tions to the signals (for reasons discussed below), but can still be used. If
costs are a major issue—for any number of reasons—digitization of existing
materials may be a viable option, provided they are available and this form of
use is permitted. Many copyrights on maps prohibit using them as the basis
for digitization. Assuming that the maps are available and not copyrighted,
digitizing GI can be a good compromise and a reasonable way to collect posi-
tional information.
Surveying
With the increasing use of specialized technologies, surveying has become a
complex field, but very basic surveying techniques for hobby or curiosity can
be practiced by most people. These techniques are elementary and the pro-
cess requires a minimal amount of mathematics and geometry. The empha-
sis in this presentation is on the broad understanding of surveying, but this
section will also lay out some of key issues for advanced legally and disciplin-
ary regulated surveying. More and more people survey, which makes it ever
more important to know what surveying is and why and when regulations
and licenses of surveyors are necessary.
What Is Surveying?
Surveying, broadly understood, is the field collection of positional and
attribute information using direct and indirect measurements. More nar-
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