It looks like using a GPS for locating features on my 10 wooded acres
would be a real bonus. Especially since my wife cannot tell where she
is on the parcel. There are many available for around $100.00. I don't
really want one for driving directions, or that has a bunch of maps in
it. I just want to know, with reasonable accuracy, where I'm standing
in relation to a map of the parcel. It looks like a 3 meter circle is
standard accuracy for the $100.00 units. I think this will be OK. So,
opinions and advice please because there are so many options and so
many well educated folks reading this NG.
Eric R Snow
3 meters for a low end unit CAN be seen on a good day, with clear skies. One
thing you need to remember is that GPS units do not work well (or even at
all) under shade trees. If you're trying to locate things on a wooded lot,
you're not going to be pleased. They MUST have a clear view of the sky to
work, and they MUST pick up at least 3 satellites to work (the more
satellites they can see, the better the accuracy).
The el-cheapo ($100) one that I have experience worked fine as long as
there was blue sky in all directions. Standing under a tree blinded it
to the satellites. They work at 2.5GHz (IIRC), which is strongly
attenuated by wood, either still in a tree or dried and made into a house.
A more expensive unit could probably handle the attenuation, but then
it'd be more expensive...
It may be more effective in the end to discretely mark the trails, and
note them on your map.
I have used both the Garmin ETREX and the GPS60 (non-mapping version)
for a use similar to what you describe. Either worked perfectly for
that use, the etrex is sold for around 90 bucks in lots of places. The
GPS 60 has a few more features for around 150.00. Both let you mark
points you want to save and allows you to navigate to them, and can
create a record of the path you walk. The etrex is simpler, so that may
actually be an advantage. I like the USB port on the GPS60, as I often
upload and download stuff, but the etrex will do that also vis RS232
(you need a special connector, garmin wants 30 bucks for it, so I made
my own. Using a mill. Machine shop content). I use my GPS 60 all the
time and love it. Most excellent unit for that type of use. The GPS 60
seemed to have the best battery life for the "big name" units of
similar cost, at least when I got mine (early last year), but that may
have changed by now. I have not used any other brands, so I cannot give
an opinion on any of them.
There is freeware/shareware on the web that allows you to
upload/download locating and waypoint data from your computer, that is
better than the stuff that Garmin bundles with the GPS60. It will
download topos and ariel photos from the web (mostly USGS data) and
then put your waypoint data on it. Way cool.Works with other brands of
GPS also, I think. The name is escaping me at this moment, but I can
find it at home, if anyone is interested.
Hope that helps,
On 20 Mar 2006 08:24:15 -0800, email@example.com wrote:
The Garmin web site said that most GPS units will not work indoors,
but will work in the woods. Posts previous to yours said that woods
will block the signal. Of course, the density of the trees will
determine the blocking potential. Your post is great though because
you are using the GPS with success just the way I want to.
I like hunting for meteorites. When you find one, there is usually a pear
shaped debris field where you can find more fragments of the main body. You
then set up search grids with those orange soccer cones.
If I have to leave, I know that I can come back next weekend, and find this
needle in a haystack. Within ten feet. Try that with a seven bux map.
Would that be like putting an X on the bottom of the boat when you find a
good fishin' hole?
Eric R Snow wrote:
from the web (mostly USGS data) and
The website is correct, it won't work indoors, the signal is heavily
attenuated by most construction. I generally use mine in the woods. How
the new england woods compare to where you are, is hard to guess. I am
not any sort of expert, but as I said, i generally use mine in the
woods, when hunting, hiking, etc. I've never had occasion to try it in a
rain forrest, but it has worked around here for me thus far. I still
carry a map and compass if I am in unfamiliar areas. I usually only want
to be able to navigate back to my truck, camp, stand or whatever, should
I get completly turned around, so the mapping is not a big deal to me.
My unit gets me plenty close for that. I have not had problems getting
reception in the woods. Where I am, there are usually 5 or more
satelites in view, so perhaps that gives the unit enough "choices" that
at least 3 are useable most of the time. I understand that can all be
very area and terrain dependent, so YMMV, as we say.
Someone else gave an excellent bit of advice, find someone you can
borrow one from, and try it out. That is exactly what I did. I tried a
friends etrex and loved it. I got the gps60 because my wife liked it a
bit better than the etrex (longer battery life rating & better antenna),
and bought it for me. Great woman, she is. I'm keeping her.
" . . .I just want to know, with reasonable accuracy, where I'm standing
I've had GPS since it wasn't cool - Garmin GPS 45. I still have it. If I
understand your question correctly you wish to locate specific points in
your parcel of land and then reference those points to a map. In order to
do this you must have a highly detailed map to begin with. I can't say with
any certainty how detailed that map should be. I don't know of any sources
that have maps of sufficient detail for one to pinpoint locations within a
10 acre parcel. The DeLorme maps of residential areas are an exception,
but I assume your parcel is not residential.
The GPS will give you the latitude and longitude coordinates of any point
you pick to "waypoint". This means you hit the waypoint key and the GPS
records the current location as a point for future consideration. Then to
find that waypoint on a map the map would have to show sufficient detail to
discern a specific plot of 10 acres. That would be a very detailed map,
indeed. AFAIK, such a detailed topo map doesn't exist. Maybe there'd be an
aerial map of the specific area, maybe not - I'm not sure about that.
So, getting back to "waypointing". You could walk the parcel and "waypoint"
as many spots as you'd like. This in essense, stores a map of the parcel in
your GPS. You could then open the "page" that contains the map you just
drew and walk over it and see a moving cursor defining your present position
on the map.
Some GPS's can be read on a PC and allow printing of the maps (pages). This
would allow you map the area with as much detail (numbers of way points) as
you desire and download the map to a PC and printer.
On Mon, 20 Mar 2006 11:17:34 -0600, "Robert Swinney"
My plan is to use the legal description which gives the latitude and
longitude descriptions. And the county also has recent aerial photos
it uses for keeping track of changes. My brother, the geologist and
cartographer, is going to use this info to draw a map which will
basically be a rectangle with the outline of the triangular parcel in
question within. A grid will be drawn on this. The line spacing of the
grid will be either 10 or 20 feet. Then I can place marks on this map
and show my wife where things will be in relation to existing roads
Go for it, Eric! GPS's are very practical devies. Lots of fun also. I got
into GPS many years ago from a limited background in celestial navigation.
It was a natural step - I bought a GPS instead of a new sextent. I'm still
interested in celestial, though. One of my shop dreams is to build a
A friend of mine in the UK is building his own sextant and has put together a
web page covering his efforts.
You may want to check it out.
Home Shop Freeware - Tools for People Who Build Things
On Mon, 20 Mar 2006 15:28:04 -0600, with neither quill nor qualm, Rex
There's a good straight-line there somewhere, I'm sure. <g>
Has anyone looked into Google Earth? You can see your property down to
one meter resolution through the satellite's eyes. It's downright
www.earth.google.com Download the app and view away!
I don't have the PC power to run "Earth", but I've looked up our house
on the sat pix in Google Map's. There is a stone wall running down the
middle of our back yard. It's 2' wide max and I can see it on the
So, if that's the resolution available to the public, for free(!), I'll
bet the military satellites can see when my shoe lace is untied!
RE: Maps, check for USGS maps online, possibly available for download
from a university site. The USGS maps and photos for the CT area are
available on one of the UCONN servers, check universities in your area
RE: Reception, if you do have trouble getting reception in the woods, an
external GPS antenna mounted to the end of a telescopic painting /
window washing pole may elevate the antenna enough to get a decent
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