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General => General Forum => Topic started by: Rich_B on June 17, 2006, 12:06:58 PM

Title: -Land survey how to do by your self
Post by: Rich_B on June 17, 2006, 12:06:58 PM
I picked up 20 acres .need to figure out how to use gps to find corners..Have been told that there  is a marker in nw corner .went out thee once. I could spend the funds for survey would rather use the funds for putting septic  so to get started on building.Reading this forum seems like some knowledgeable people here so thought I would ask . :-?
Title: Re: -Land survey how to do by your self
Post by: glenn-k on June 17, 2006, 12:24:58 PM
I haven't done a lot on the ground with GPS - lots of flying with it.

I would say get a map that shows your plot of land with measurements -- assessors parcel map has this--locate the corner first corner then follow the directions and measurements to the next corners.  

Note that I have heard of discrepancies between the GPS and surveys done manually by the surveyors.  

If you are building at all near the property line and don't have the rest of the corners positively, it would be well to call the surveyor in.  There is nothing worse than to find that half your house is on the neighbors property.  Note that while the local inspector is supposed to check setbacks to make sure this doesn't happen I find that he commonly assumes that you did it.
Title: Re: -Land survey how to do by your self
Post by: bartholomew on June 17, 2006, 01:38:26 PM
Finding survey monuments can be very difficult. The monument itself would typically be an iron post barely sticking out of the ground or completely buried, or a lead plug set into a hole drilled in rock and flush with the rock surface. If the land was subdivided a long time ago, the monument might consist of nothing more than some buried broken pottery or glass. To make it easier to find, the surveyor might have put a white wooden stake next to it (rots away quickly), some fluorescent survey tape (fades and deteriorates), or a pile of rocks. If you've got a survey plan, it might indicate the type of monument. A solid circle typically means an iron post while a solid square means a lead plug. "IP" also means iron post. If it's a lead plug, you know it's set in rock. An iron post could also be grouted into rock but usually is dug into the ground.

You will need one of the following:

1. A survey plan showing the distance and direction from a known starting point that you are able to locate on the ground. If your gps allows you to enter distance and direction (aka range and bearing) then it's pretty straightforward. Just make sure that the gps is set up to use the same distance units as the survey (or convert them). If your gps doesn't take distance/direction, then go to the starting point, get its coordinates, and then bust out that highschool trigonometry to figure out the coordinates of the other corner. Before you take the measurement, make sure your gps coordinate system is set up to use WGS84, NAD83 or the appropriate state plane coordinate system. Check the gps measurement units. Most likely they will be in meters so you will have to convert the survey plan distance into meters as well. If you gps allows, you can get much better accuracy by setting it down and allowing it to average out the readings over half an hour or so.

2. The exact lat/long or northing/easting coordinates of the corner. Does your county or other govt agency provide an online GIS or mapping system? If it does, zoom right in to the corner of your property, place the mouse pointer right on the corner and hopefully it will display the coordinates somewhere on the screen. Then you'll need to know what coordinate system and datum are being used. Hopefully it will tell you in a help page somewhere. The datum is likely to be either NAD83 or NAD27. The coordinate system could be lat/long, UTM or state plane. Whatever it is, configure your gps to match. Also check for the accuracy of the online system. If it doesn't tell you somewhere, then you could get the coordinates for a point you know you can find on the ground and compare that way.

You might want to rent a mapping grade or better yet a survey grade gps. They will give much better accuracy than a consumer gps, and they have much better antennas and signal processing circuitry so they can often lock into a signal where the consumer gps can't (ex. in heavy forest). I can get a survey grade here for about $500/week; not sure about the daily rate.
Title: Re: -Land survey how to do by your self
Post by: Rich_B on June 17, 2006, 02:29:22 PM
Thank you for replies.I was out there and got close to the property .as you said glen I don,t want to find the house half way over line or not meeting the set back. Bartholomew what you said about changing the gps is what I was having problems with.I have delorme tpop program and could not figure out how to convert it to the other measurement .I can build and do all the work for my site development.I just never had to find corners  Thanks again  8-)
Title: Re: -Land survey how to do by your self
Post by: Bouncer on June 18, 2006, 10:06:31 AM
Also remember that when you follow the degrees that they are different from a regular compass.
surveys have there own system. So the degrees on your deed will not match a compass degree.
Kevin
Title: Re: -Land survey how to do by your self
Post by: glenn-k on June 18, 2006, 11:17:00 AM
If using a magnetic compass don't forget about the deviation between true North and Magnetic North.

(https://i35.photobucket.com/albums/d184/glennkangiser/magerraticr.gif)(https://i35.photobucket.com/albums/d184/glennkangiser/magusar.gif)
(https://i35.photobucket.com/albums/d184/glennkangiser/magcomsetr.gif)
Title: Re: -Land survey how to do by your self
Post by: Pala on June 18, 2006, 10:47:59 PM
Also, the USGS topo quad map will have the local magnetic delclination.  If you decide to do it the old fashioned way with analog tools.
Title: Re: -Land survey how to do by your self
Post by: MikeT on June 19, 2006, 11:07:55 AM
I had two of my pins in the road (with an easement to the county), so two of my markers were simple to find.  The problem was my other two markers were located down a 39% slope and in a bunch of blackberries.  Since one neighbor has been a constant complainer to the county (the county folks warned me that he is unreasonable), I knew I needed to know exactly where our common property line was, so I hired a surveyor to locate the one corner.  The surveyors were already going to be in the area, so the cost for locating the one marker was $160.  I was glad to pay that because I had tried to use a metal detector and a compass (with the appropriate adjustments for the declination, etc).  Turns out I was grubbing around about 10 feet too far into my neighbor's property.  Then from that point I was able to take the assessors survey map and find the final corner (after hacking through lots of blackberries and digging with my hands on my knees.  As was stated earlier, there was a rotted stake marking the general location with the actual pin having a faint teflon surveyors tape on it, and the pin was buried save for about 1 inch.  Now I have all four corners marked and a string between the markers makes it easy to hit my setbacks, and such.   Now I meet with the excavator and things will hopefully really start going.  
Title: Re: -Land survey how to do by your self
Post by: bartholomew on June 19, 2006, 01:33:39 PM
Rich, if your question is about how to change the settings in your particular gps, I can't help you. You might try asking on a gps user's forum like http://gpsinformation.info/forum/
Title: Re: -Land survey how to do by your self
Post by: Rich_B on June 19, 2006, 09:32:03 PM
There is only 1 pin no others I would like to get close to the line .I will build in the middle .lot size 660'x1320' so should be alright if i get with in 50' .nearest house 1 1/2 mile other than tat just cows put some water out for them they will be happy and owners of the cows will like it more wieght gain not walking for water.Getting off subject yes the gps was what giving me fits convert measurement.SUrvey use gps a better one granted from what I under stand it should get me with in 3' a new puzzle  for me. Wanted to be building by now but other hold ups be lucky if I can start by august .three mounths to finsh so I can move in be for bad weather.Cutting it close ::) thanks for the in put you never know when someone will hit what I have been missing  ;D
Title: Re: -Land survey how to do by your self
Post by: glenn kangiser on June 19, 2006, 10:21:20 PM
Also, possibly your neighbors know where their lines are and could show you their corners -then by measuring from theirs you could get close to yours.
Title: Re: -Land survey how to do by your self
Post by: Amanda_931 on June 19, 2006, 10:54:20 PM
With my Nashville house, the lot was officially 55 feet wide.  OK.  The lot next door was also officially 55 feet wide.  Except that the pair of lots had once belonged to a divorcing couple.  They wanted to split the land in a way that each lot could have a legal house with septic tank on it, i.e., 55 feet wide.  But, there was a short retaining wall between the houses at 50 feet.  The absolutely logical place for the property to change owners.  Coming over the extra five feet to make the neighboring--by now, just lot--a legal housing lot meant that the property line went through my garage.

My guess had we gone to court the end result would have been that the lots would have been declared 60-50.  Kind of moot because the area is zoned industrial and nothing that looks like a house can be built on it.  Possibly even, after the fire, within the original footprint of the house.

good to know your boundaries!