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Mapping Sharon's Trails
by Kurt Buermann
Fall 2004
 A Sharon Friends of Conservation watchword is “promote.” We
hope to promote a better, wider appreciation of Sharon’s
conservation lands by leading hikes. Another way we are supporting
this goal is mapping Sharon’s hiking trails. A map of the
King Philip’s Rock and Perkins Conservation Land is presently
available.
This spring Jim Barron and Kurt Buermann dusted off the GPS tracker
and began an exploration of the Massapoag Trail. A preliminary
map is now available with a finished version due in another month.
The procedure is to walk the trails wearing a hat with a small
Global Positioning System (GPS) unit attached to the top. Strange
as it appears, height insures the GPS satellite signals (from multiple
satellites) are not inadvertently blocked by the body as a low
satellite would be if held in the hands or pocket. If you think
of the GPS signals as beams of sunlight, you can see how an object
on top of your head would be illuminated while a low sun behind
you would throw a shadow on an object held in lower in the hands.
It is also important to map in the spring or fall when foliage
is at a minimum. The GPS signals are very weak and can be blocked
by dense leafy overhead.
Stage two is to download the GPS tracks onto a topographic map
program. This provides a picture of the tracks on an actual map
background of woods, wetlands, hills and dales.
At this point a transparency of the tracks can be made for projection
and tracing on to a more detailed map than provided with the basic
Topo program.
SFOC has been very fortunate in having the assistance of April
Forsman of the Town’s Engineering Department provide some
high quality maps using the Massachusetts GIS (Geographic Information
System). In general these maps are more detailed than those available
on the retail market.
There is, at the end, a process of hand drawing. For example, where
GPS mapper has veered off the trail to investigate a false lead
and returned, a confusing side spike will show. This can be edited
out with a computer program. Another curious phenomenon is to see
the GPS track offset from known landmarks—say the end of
a street. This is because many maps were made before GPS, with
its uncanny accuracy of down to 20 feet, came into use. Here again,
hand corrections must be made.
In addition to mapping, SFOC members have renewed original faded
trail markings as well as done some trail grooming, particularly
as concerns greenbriar growing across paths. Trash is also removed
as we go along. Where needed we supply guiding signs.
Anyone interested in a preliminary SFOC map of the King Philip’s
Rock area or Massapoag Trail may email kurtb7@juno.com or write
to SFOC, 45 Furnace St., Sharon, MA 02067.
Back to Sharon's Hiking Trails
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