GPS IN The Sugarbush

[mapleman3]

if there is an interest in GPS we can add a heading for it, for now post your questions and ideas here. I'm sure we have some here besides The Clan Deleney and I who dabble in GPS for fun and maple.

[Cardigan99]

Jim, I'm all for it. Last year I marked with my spiffy Garmin 3600 then transferred the coordinates by hand to a piece of graph paper. With that you can get a really good idea of main and lateral lengths. Unfortunately the Garmin went on the fritz in Sept. Hope it's just the battery.

[forester1]

Good idea. I used a garman 76S to follow the route of my proposed mainlines. It lays down a track on the unit and gives the total distance, then you can produce a map. Also I noticed big blank areas across hillsides that I can now look for the best route. I can get a good estimate the total line needed.

[Maple Hill Sugarhouse]

post edited.

[Cardigan99]

Valley View, I'd love to see one of those if you don't mind.

[Clan Delaney]

I've got overhead pics of one of Jim's sugarbushes that I made with GPS data he collected in the field. I'd like to post them, but the 'ol computer is glitching and I'm at limited capacity at the moment. I'll get them up as soon as I can. Interesting stuff. Lets you see trends that are almost impossible to see on the ground.

[adk1]

Now your speaking my language. I am a County GIS Administrator. I do all of the computer mapping/analysis. I also use GPS for some purposes, but it not a recreational GPS. It is a Trimble GeoXT that provides me with sub-meter in the field accuracy and close to sub-foot accuracy post-processed.
Anyways, many local counties have free online GIS websites that will provide you with your tax parcel and orthoimagery (digital imagery). Some sites may even allow you to input coordinates. These sites may prove to be very useful to you. You should investigate through your County or even your local Town, some more affluent Townships may have the ability to house thier own site.
If anyone would like to see the site that I am in charge of here at my county, feel free to goto this address

http://74.39.247.67/gis/

[Clan Delaney]

http://www.trimble.com/graphics/products/geoxt-2008.jpg

The Trimble GeoXT. Daaaaang! Now THAT's a handheld GPS! Hold on a sec, I'm drooling on the keyboard....

[Acer]

Used mine yesterday to get an overhead view of 120 tap woods.
First time tubing a sugar bush, so getting the overhead view helped a lot.

hard to explain but when planning the mainline, it was a great help to look at the lay of the land, and the tree locations on the gps and the mainline location became obvious.

Dean

[H. Walker]

Ok you GPS guys I'm new to this technology, is there such a thing as being able to do elevatons accurate enough to set main lines at 2 or 3%?

[Snow Hill Farm]

As far as I know that would require the $50,000 GPS setup. I work for a survey & engineering firm and that's how much the equipment costs that locks into the satellites and can give accurate vertical and horizontal elevations to the hundredth of a foot. The small hand held units generally are only accurate to within 10 feet vertically and horizontally. So they wouldn't be good for setting a main line. There is a "smart level" on the market for around $100 that can be placed on the main and will tell you the % slope, very handy.

[Clan Delaney]

Ok you GPS guys I'm new to this technology, is there such a thing as being able to do elevatons accurate enough to set main lines at 2 or 3%?

The short answer is yes, it is possible. The longer answer is it'll cost you far more than it's worth. Professional GPS receivers for surveying work are quite pricey, and for that kind of money you'd be better off buying an RO or vac system.

What you can do with a commercial handheld GPSr is map out the locations of your trees with fair accuracy and overlay that data onto a digital topo map to determine the best positions for your mainlines.

[mapleack]

Survey grade GPS units that'll provide centimeter horizontal / vertical accuracy are very expensive, and DON'T provide that high of accuracy when there is leaf cover. If you're laying out mainlines in fairly flat areas, spend $250 for a decent construction level/ tripod and use it to check your grade, that's how I do it.

[Knot E. Maple]

GPS accuracy is the question with shooting the mainline grade. Simply-put: anything consumer-level has 'not a chance'. Sink 10k into one and you could have me wondering why you're not paying someone else to do it.

So - no. GPS are useful, but the elevation accuracy is quite difficult - especially in the woods. Best accuracy is before leaf-out (or after of course). A few options exist: best perhaps is a clinometer (oh, and that's another $150 to invest - do a search for forestry suppliers).

Now, we'll really test you: If you mapped your waypoints for the bush and downloaded it to the computer, uploaded to a mapping tool (such as google earth, etc), you might be able to get your grade very close on paper. This would help in planning more than actually in the bush.

[theschwarz1]

Folks, your not going to get decent elevation until you purchase a surveyor grade GPS($$$).
Even the GIS grade GPS gives you whacky elevations. Your best bet is to get one off the shelf ($200?) and map out your taps and lines horizontally, than upload to your computer. You can then overlay in Google Earth to visualize slope (they use 20 ft interval contours).... or download the fGIS software (free GIS software) from forestpal.com and then obtain the 2' contours and latest aerial photography from your local govt GIS or planning office or from a state GIS data clearinghouse site. Load it all into fGIS and whala!

The 2' contours were flown using LIDAR (Light Detection And Ranging) in Pennsylvania. Not sure about other states.

I can offer services to do all this to those of you that are relatively near by me.

[twitch]

My hand meld gps from garmin reads exactly the same elevation as the $5,000 dollar gps in my dads Cessna. maybe its not as accurate on the ground but it is in the air.

[adk1]

Clan, that is the exact GPS unit that i use at work. pretty decent unit, it is considered a sub-meter accuracy, but after post processing, I can get down to 1-2' accuracy

[theschwarz1]

My hand meld gps from garmin reads exactly the same elevation as the $5,000 dollar gps in my dads Cessna. maybe its not as accurate on the ground but it is in the air.

What is the range of error/accuracy in the Cessnas elevation? Just curious.