Measuring Land

[WH_Conley]

Does anyone know of a site or formula to calculate acreage in boundry of land? I have the lontitude and latitude for the corners.

[Ron Scott]

Acres = length in feet x width in feet
                             43,560

[WH_Conley]

Ron, I know that part of it. I don't know how lontitude and latitude convert to feet.

[sprucebunny]

If you look on a USGS map of the area there will be a scale....it changes as you move north or south , though

[WH_Conley]

I don't know much about a GPS but could a person enter the corners as waypoints and let it tell you how far from one to the other?

[sprucebunny]

If you have a fancy GPS it might do that. There are programs that interpret GPS data on your computer and most of the Windows based ones seem to have that function. Not my Mac one , though  :(

[WH_Conley]

I got one, now to figure how to use the DanG thing, bout all I ever got out of it mph when on a boat. Reckon them things is like computers, get a 13 year old to show ya how they work?

[Tillaway]

Lots of ways to do it.  Convert from lat and long to state plane or UTM coordinates.  State plane is usually in feet, X/Y coordinates.  UTM is in meters.  Corvallis Micro Technology (CMT) has a free program on thier website called Cogo CAD.  Convert to state plane or UTM set up the program correctly and get acreages or whatever you need.  It takes a bit of patience to learn how to use it but its real handy.

There are websites where you can put in your lat and long and convert to UTM.  Or just plug them in the GPS as waypoints and change the coordinates to UTM on the setup screen.  You may need to know what UTM zone you are in, fortunately there are websites that have that info as well.

[WH_Conley]

Thanks everyone, I will look and see what I can come up with on the web.

[Black_Bear]

Go here and download the Army Corps of Engineers Corpscon program. Corpscon will convert your geographic coords to a usable numbered coordinate system.

http://crunch.tec.army.mil/software/corpscon/corpscon.html

What type of data you have and what accuracy you want to achieve go hand in hand. Be careful and be aware of the validity of your data. ie. if you mapped the corners with a handheld GPS your error can be rather large and your area estimate can have a plus or minus of 1-2 acres.

BB

[rebocardo]

> a GPS but could a person enter the corners as waypoints and let it tell
> you how far from one to the other

Yes, my Garmin did that. You could map out a whole lot that way.

Plus, you could set one way point and have it tell you when you traveled XXX number of feet to set the other and it would count down how many feet you were away from it while walking.

[Furby]

Some GPS units will get very accurate if you leave them turned on and sitting in place with out moving them for a while.

[rebocardo]

> Does anyone know of a site or formula to calculate acreage in
> boundry of land?

Been a few years since I used it to blueprint a factory building, but, I think (now) Microsoft Visio will do that if you feed in actually dimensions. It will not do it from raw coor. data.

Go to Yahoo and use these search words ( calculate acres gps software ) to pull up these, amoung others:

http://www.palmgear.com/index.cfm?fuseaction=software.showsoftware&prodID=38923

http://www.eurocool.com/author/?author=18893

This should give you everything you need :-)

[johnjbc]

Street Atlas will do it. Send them to me and I will give it a shot.

[WH_Conley]

Sprucebunny got me to  thinking, boy what a headache. Using the scale on the USGS topo maps I took a dial indicator and broke scale down to thousandths of an inch, figured how many ft per, measured the lines on the piece of property and did the math.

I checked this against the surveyed deed on the farm I live on and came very close, less than 5%.

This is close enough for what I want as I bought the property by the boundry, only reason for wanting to know is to try to get rough projections, which is a guess at best, of possible yeild on down the road.

I would not suggest this method if you need exact measure though I am sure it would work a lot better on land that had straight property lines.

Thanks everyone for your input,
Bill

[SwampDonkey]

Another way may be to use graph paper and UTM or  NAD 83 coordinates (m/feet). As long as you use a liner scale you can measure the distance between corners at the scale of your drawing to figure lengths. If its irregular, layout the plot into triangular segments and calculate each triangle. (1/2 x base x height). You can place a line segment or side of a triangle to compensate for that portion inside the triangle vs that outside. (cross hatch is outside bounds)

[mapleveneer]

There is freeware GIS mapping software available at www.globalmapper.com

Go to their download and purchase link and download the trial version.  You will need to find topo maps in a format which this program can use.  They are readily available but may be a little more difficult to find for free.  In Massachusetts they are availble for downloac from the state GIS web site.  They are also available at www.geocomm.com along with many,many other types of maps.  Again, finding the ones you want will be the most difficult part.

Once you get the topo map loaded into the program it's pretty easy to draw the property in question and it calculates acreage right at the bottom of the screen.  Larger acreages will be easier to do that smaller ones.  The Lat/Lon information is displayed at the bottom of the screen and changes as you move the cursor.  Just move it to where you want your corner and click.  Once the property is enclosed on all sides the acreage will display.

I  am no 13 year old computer whiz but with some figuring have gotten the basics of the GIS mapping stuff figured out.

If you don't want to spend the time trying to figure out how all this works, read your GPS manual.  Then navigate from point to point on your  boundary.  This will give you a bearing and a distance for each leg.  Draw this out to scale on graph paper using a protractor and ruler then figure out the enclosed area as described in the other post above.

[johnjbc]

The attached image is a screen capture from Street Atlas . On it you will see the boundary's in light green with letters at the corners. I walked the line and did a capture with my GPS at every pin. At  home I cabled up to my computer and uploaded the coordinates, then used the draw tool to connect all the points. If you right click on the line and show properties it gives you the acreage and perimeter of a closed drawing.  166.52 acres 16446.8 feet
The survey showed it to be just over 166 acers.

Will post the image when Jeff gets the gallery working

Good job Jeff

Below are the plots for the boundary shown on the map

39.882967, -78.156117, Gate
39.883017, -78.156117, A
39.881083, -78.156717, B
39.880233, -78.155250, C
39.879050, -78.156617, D
39.877367, -78.155283, E
39.877450, -78.153667, F
39.890433, -78.157150, T
39.878500, -78.152750, H
39.878433, -78.151733, I
39.878650, -78.151250, J
39.878700, -78.150050, K
39.879783, -78.147433, M
39.879000, -78.146233, N
39.879000, -78.145417, O
39.880183, -78.146450, P
39.880300, -78.146333, Q
39.884617, -78.163783, Power Line
39.888400, -78.152167, W
39.878067, -78.152933, Gt
39.879650, -78.149700, Lt
39.884983, -78.157583, Turn Off
39.884350, -78.152617, Stage Area
39.881700, -78.147400, Buck Rub 1
39.883133, -78.150867, Buck Rub 2
39.886900, -78.150767, Dead End
39.880698, -78.153895, STAND
39.884984, -78.157586, TURN-Off
39.892141, -78.154421, S
39.888386, -78.151921, NARROW
39.889560, -78.154072, U

[johnjbc]

These are the same Way-Points loaded into DeLorme 3D TopoQuads

[rebocardo]

cool topic, computers, you can hate them, but, you have to love them too 

[Kirk_Allen]

Looks like you might have a few select intersections on that there map that would be ideal for a deer stand ;D

[SwampDonkey]

Yes, they look to be well placed in those gullies, according to the contour map. ;D

[johnjbc]

Yes the Deer hunting is good. Its located in the center of  a tract about 12 miles around with farms on all sides. When hunting pressure starts the deer come visit me. :D :D
This is my favorite Deer Stand. Its 100 feet from the trailer and will be my front porch when the cabin built



View from the stand


View without the snow. Notice how open it is. The hurricane flooded the entire valley and washed all of the under brush away.


My deer. Shot from the Blue Barrel.


Larry's deer He got 2 with his 41 magnum pistol this year.

[SwampDonkey]

Another way may be to use graph paper and UTM or  NAD 83 coordinates (m/feet). As long as you use a liner scale you can measure the distance between corners at the scale of your drawing to figure lengths. If its irregular, layout the plot into triangular segments and calculate each triangle. (1/2 x base x height). You can place a line segment or side of a triangle to compensate for that portion inside the triangle vs that outside. (cross hatch is outside bounds)

A little fixer upper to this post.

If your triangles are not right angled, then what?

You have to do the calculation for area in two steps.

First find the coefficient of the triangle, we'll call it S.

S= 1/2 (a + b +c)

Then find the area A

A= Square root {S x (S-a) x (S-b) x (S-c)}

You could set this up in a spread sheet to do the area of a property with straight sides, with length of each side known.

Example: I have a triangle with sides measuring 5, 8, and 12

S = 1/2 (5 + 8 + 12) = 12.5

A = Square root {12.5 x (12.5-5) x (12.5-8) x 12.5-12)}
A = Square root {12.5 x 7.5 x 4.5 x 0.5}
A = Square root {210.9375}
A = 14.5237

or it's 1/2 the two known sides times the sine of the interior angle of the two known sides.

to find the length of an unknown side "a", two sides known and their interior angle (alpha) is known it's:

a = square root{ b² + c² - 2bc x cosine (αlpha)}

Spreadsheet attached.

[SwampDonkey]

If you downloaded the spreadsheet 5 minutes ago I had to upload it again with a correction. Excel only does trig on radians, so I had to convert to degrees π/180 for the unknown side calculation.