One important point to clear up is that corner and monument are
not synonymous. A corner is a point on the earth's surface determined
by the surveying process. Its location is marked by a monument which
is the object or physical structure that marks a corner point. For
that reason an existent corner does not necessarily mean that the
monument is still there. An existent corner is one whose position
can be identified by verifying the evidence of the monument, or
its accessories by reference to the description in the field notes,
or by an acceptable supplemental survey record, some physical evidence
or valid witness testimony.
An obliterated corner is a point which has no remaining traces
of the monument, or its accessories, but whose location has been
perpetuated or can be recovered beyond reasonable doubt by the acts
and testimony of interested land owners, competent surveyors, other
qualified local authority or witnesses, or by some acceptable record
evidence. But if a corner monument can be destroyed or covered over,
and still there is an existent or obliterated corner point, what
then is a lost corner?
A lost corner is a point of a survey whose position cannot be determined,
beyond reasonable doubt, either from traces of the original marks
or from acceptable evidence or testimony that bears upon the original
position, and whose location can only be determined by reference
to one or more interdependent corners. Such an interdependent corner
is also called a control corner or controlling corner. It has been
identified as an original interdependent corner and thus, can be
used to control the proportionate position of a lost corner.
The definitions of existent, obliterated and lost corners can be
found in the manual at 5-5, 5-9, and 5-20, respectively. As an aide,
the Glossaries of Surveying and Mapping Terms is included with this
course and can be accessed at anytime by selecting the Glossary
button on the navigation bar.
At this point in the course, you will have an opportunity to recall
and apply what you have learned.
Next, get ready for a review exercise!