GPS Help

[pcdreams]

I know very little about GPS. But, what I'm looking for is a consumer unit that will allow me to walk my property. mark certain points along the way. preferably connect to a computer and I can import the points into cad or something and print out a map.

I'm trying to get a pretty good idea of distances etc. I'm hoping to find something that would be accurate enough I could use it for a site plan to file with whomever I need to.

[OkieDavid]

The biggest difficulty is obtaining the accuracy you need for anything meaningful. The surveyor grade unit we use at work has sub centimeter accuracy and will download points into a shapefile using Arc GIS. The downside is it cost upwards of $80,000.00. Your standard GPS unit for civilian use is rated for 3 meter accuracy +/-. As this equals to about 30 feet its use is questionable. 30 feet will get you close enough to find your hunting stand or vehicle but not near close enough for practical use as a srveyor. I have a Garmin E-trek that often gives me accuracy of around 1 meter although the manual clearly states +/- 3 meter. That said, about all of the handheld units have download capability.

[Bearfootfarm]

What Okie said

I prefer Garmin units myself

[texican]

Have you tried Google Maps? You can get some pretty good detail, and find individual landmarks easily, if you know what your looking for. I can see shovels and other tools laying about on the google map of my place....

[farmerDale]

A meter is only 39 inches. So within 3 meters is within 10 feet, not as bad as 30 feet. I have an old handheld magellan I use moose hunting. Trouble is in the forest it is hard to get a signal at times. i bought it in 1999. It is accurate within about 20 feet maybe. Close enough to find a moose for sure!!!

[Murramarang]

When a GPS takes a measurement it is accurate to within its limits. That accuracy can change from minute to minute due to atmospheric conditions (or if you like, signal strength). If you just take one measurement, then you run the risk that at that point of time, the signal was slightly off. The way to get around this is to take multiple measurements and average them out.....even go back to the same places on another day and take more measurements.

Most of the GPS you buy have an averaging function.....this means that if you stand on one spot and hit the function it will take multiple measurements and average them out for you. This is a neat function - but to make the measurement even more accurate, go back on a few different days and average out all the measurements.

I know that could be a pain - but its the way to get the most accurate measurements using the most basic equipment.

Using Google Maps is also a great idea - but sometimes the images are a little old (one to 5 years) and so make it hard to get a good fix.

Hope that helps

[Chuck R.]

I use a Garmin Etrex HCX for hunting, scouts, and an occasional geocache. It’s a pretty good little unit as it has a memory card and you can upload maps in color. Battery life is pretty good at 20 hours on a couple AAs.

You can download your waypoints into Google Earth (free download), which has a pretty decent measuring function. I use it quite a bit to plan for land mods, build range cards from my stands, and I used it to layout my range. When used with Google earth, you can see the elevation points of intervening crests etc. I then capture a picture (.jpg) and past it onto PowerPoint so I can build overlays and models. I used it this way to apply for my barn building permit.

I’ve used mine a couple times to set up geocache courses for our pack. With it, I can build the course, print out maps for the walking-leaders, and then send them the point files so they can upload into their units.

I’ve gotten accuracy down to 7’ a couple times, you’ve just got to be a little patient, and wait until the accuracy increases before capturing your point. It’s not anywhere near surveyor accurate, but it’s a heck of a lot better than a big finger on a little map.

Chuck

[pcdreams]

excellent thanks guys. Now I know what to save for

[Coloneldad5]

Me personally I prefer the Garmin because it is one of the easiest to use and operate.

As stated here, the current GPS system is not all that accurate for marking plots. You are lucky if you can get it down to 3 meters +/- which means a 20' diameter circle. But that can be impacted by vegetation, weather, solar weather, etc. In reality you are probably more in the range of 10 meters (about 33') radius as the average accuracy. The current system as it's opened to the public will generally only support that. The military is getting ready to improve the system (plan on 5-10 years at the earliest for it's implementation) which will improve (for the military) accuracy to less than 1 meter. The fallout is that civilian usage will also improve some too. This newer system will have stronger signals to work better in heavy vegetation and buildings.