OT: GPS unit for survey

The first thing to do is to see if was surveyed in the past and who did it. If they have done it in the past it will be easy for them to update their survey.

The second course is to see if the adjacent properties were surveyed and talk to the surveyer that did them.

The third would be to see if the area was aerial surveyed and if the aerial survey is available.

The shape of the property and if a surveyer has to come on the property will determine the cost of the survey.

If you are required to have the survey done by the title insurance company, use the same title insurance company as was used before and they may just update the title insurance without the survey.

John

Reply to
John
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Not a bearing point, but one of known elevation (Bench Mark). The description put it as being a brass plug with reference line set in the east wall of the pig barn, eighteen inches down from the top surface, on a certain farm. On arrival at the farm, I introduced myself, and the owner gave us the run of the place; an hour latter, seeing our frustration, he asked what we were looking for, then explained that the building had been doubled to the east. He showed me the old foundation with about three inches exposed above the "dirt" floor and I made the decision to employ an alternate reference datum. Gerry :-)} London, Canada

Reply to
Gerald Miller

Check your math! 2° ± in 1/2 mile gives an error of approximately 92 feet. ± 2° is saying that the desired point is within a 4° range. That would approximately 184 feet in a half a mile. Hire a surveyor.

Ivan Vegvary

Reply to
Ivan Vegvary

And if you don't know the basis of bearings of the monuments you could be off by the magnetic variation from true north. Up to 17° depending what part of the country. Lots of error! Hire a surveyor.

Ivan Vegvary

Reply to
Ivan Vegvary

Get a Garmin E-Trx Summit. It has a flux-gate type compas and aneroid barometer built in. The compass is very accurate when standing still. GPS direction finding only works when in motion.

Reply to
clare at snyder.on.ca

accurate. About the same as my old

One degree error at one-half mile is about 40 feet.

John Martin

Reply to
John Martin

You need to use one first before you pass judgement, If you take the shots in short lengths and back shoot to check for error. The accuracy is up to the operator---like a machine tool. I stand by my statements been there done that. Ask any timber cruiser, mine engineer ect...I do a bit of real estate work and check property line with surveys ect. and find a Silva Pathfinder to be as acccurate as a Garmin E trex and I usually get within 4-6 @ 1/2 mile of know points---on a good day without a lot of terrain ect. for recon purposes

I was refering to a *recon* survey and also recommended he hire a pro--diy survey is like a diy root canal...asking for trouble. Read the language used on FS easement that cover the surveyors ass---something like any errors found in the future stand as the easement..

ED

Reply to
ED

Magnetic declination adjustable compass's are the standard. Use USGS topos to get the amount, it's posted there. Interestingly the newer maps have change over the past 20 years by 4 degrees in my area. The monuments I was refering to are the brass caps for quad points...or a reference to them if possible, It can get tricky on a correction line.

ED

Reply to
ED

In the early 1950's, my father was involved in the staking of mining claims during the uranium rush in mid central Ontario. His favourite story involved the staking of an area which had been in the path of a tornado some seven years previous. Imagine pacing a compass line while crawling over tangled swamp timber some twenty or so feet above ground. Gerry :-)} London, Canada

Reply to
Gerald Miller

Any magnetic field sensing device is effected by deviation and variation in the earth's magnetic field. I dont remember which is which but the one is an error caused by the north pole not being at the same place as the magnetic north pole. The other is caused by local magnetic material in the area. For example the border between NY and NJ is an slight arc but was supposed to be a straight line. It was surveyed right after the end of the revolutionary war. The arc was caused by the magnetic deflection from the iron ore deposits in the area. A gps survey would not show a curved line.

John

Reply to
John

On a gps, you can load a present position and go to another position and it will give you the exact angle.

John

Reply to
John

Glenn mentioned a tree stump on Google Earth. Intriguing that we now have access to such maps as Google Earth. I have a question re. Google Earth. I have heard, or read, somewere that there is a "deluxe", extra cost version of GE. I have been unable to find anything re. Deluxe GE on the Google Web Site. But then again, I haven't looked very hard. Has anyone any inofrmation that may steer me into the right direction?

I'm not sure about Glenn's tree stump but my primary GE reference is a patio table in my back yard. Can an enhanced version of GE be any better than that?

Bob Swinney

Reply to
Robert Swinney

Thats a good story, blowdown timber and rockslides are easy to break a leg on. Phelps Dodge has agents working overtime in this area--I wonder what they know.. Haven't seen them but have found a couple of new claim tags. Rumor has it they're claiming over anyone who hasn't kept proved up. Maybe a new metals rush?.

ED

Reply to
ED

The pay version does not give you better than the imagery that is available for the free version.It allows a larger printed picture, if you pay. It does give you some business related functions that are useful for research.

Read the FAQs and

formatting link

Cheers Trevor Jones

Reply to
Trevor Jones

Check out Aero-Graphics, Inc. and visit their site. Look at the differing degrees of resolution they offer. Incredible.

Steve

Reply to
Steve B

Resolution varies considerably depending on what Google can get without paying outrageous royalties. In my case the county engineering department paid for a full aerial survey about 3 years ago and released the moderate resolution version to the public. (The tax assessor's site has the really good pictures and charges for them.) It is good enough to see things down to about 2'. Just to the north of me where the new Bass Pro outlet went in you can see shingles on the roofs. Must have been a private survey for that development. OTOH over in Crawford County my peach trees just look like blurry dark lines.

The really fun part is overlaying GPS routes. I kept my GPS on for our BVI sail last June and overlaid it on Google Earth. Then sent it to my crew so they could "sail" the whole course all over again.

Reply to
Glenn Ashmore

Can anyone answer this question about Google Earth? ...........

on some maps, it is very clear. On some of the maps, it looks like runny water colors. Did the satellite just not get a good shot on that pass or what? And will those areas ever be improved to be as clear as the others?

Thanks.

Steve

Reply to
Steve B

If you'll look at a long shot, say 100 mi. alt. or higher, you'll see the long rectangular patches from satellite passes (at least that's my interpretation). That's where the higher level of detail exists. I don't know the source of the rest of the data, maybe a geosynchronous bird.

Pete Keillor

Reply to
Pete Keillor

The imagery is a composite of sattelite and aerial photography, that switches from one to the other as resolution requires it.

Not all areas have the same resolution coverage. Some areas seem intentionally downgraded (I noticed it on some airports)

If the area does not have detailed air photo coverage, it gets a fill based more or less on the sattelite imagery and adjusted for the resolution requested from the user. Not exact, but pretty close to reality, with water where water is supposed to be and greenery, etc.

You will note that there are darker areas, as you move closer to the surface of the planet from space. These are the areas that have the detailed coverage. The tendency is to have detail of the more populated areas, o those with some interesting stuff in them.

Cheers Trevor Jones

Reply to
Trevor Jones

Thanx, Trevor ! I wondered if the imagery could be any better with the extra cost version. I suppose the larger printable pix is why I am seeing aerial photos on some mapping software now.

Great thing, that Google Earth ! In September the wife and I went on a steamboat cruise on the Delta Queen from St. Louis to Cincinatti. Pre-cruise I took some waypoints from Google Earth along the Miss. and Ohio rivers. Then it was great (but slow) fun to watch for those waypoints on my Garmin GPS 45.

Bob Swinney

Trevor sez: "> The pay version does not give you better than the imagery that is

Reply to
Robert Swinney

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