Layout a simple fence line?

we’re a few hours into trying to use SW maps and google earth pro to simply layout fence post locations at 12’ intervals between two points.

trying to make a path between the two points and then measuring doesn’t give you a way to actually mark the points so they show up as coordinates in a kml file.

I think the survey apps that cost thousands have tools for doing this

I don’t know if you are trying to mark out a fence between two of your points, or if you want to mark out a fence in relation to the property line like surveyors do.

If you want to mark out a fence in relation to the boundary, you need to know that in the United States, parcel data is most often given in a coordinate system based on NAD83, using the so-called State Plane Coordinate System (SPCS), which is divided into zones and is not the NAD83(2011) system.

Arizona utilizes a State Plane Coordinate System (SPCS) with three zones: West, Central, and East. The system uses easting (X) and northing (Y) coordinates to represent locations within these zones.

Your town is located in the central zone.

The boundary points of the parcels are measured in the following way:

  1. GNSS measurement with position in NAD83(2011) EPSG:6318, i.e. 3D system (exactly EPSG:6318 is NAD83(2011) without hight),
  2. transformation (projection) from NAD83(2011) to SPCS for the specific zone in which your town is located, in your case to NAD83 / Arizona Central (ft) EPSG:2223, i.e. 2D system.

Some GPS receiver software has the ability to automatically transform measurement results from a 3D system to a 2D system, in this case from NAD83(2011) to NAD83/Arizona Central(ft) and during the measurement you can compare the result with the coordinates and distances on the map in NAD83/Arizona Central(ft).

I don’t have such software and I use the very popular QGIS program, where I can draw points and lines. Additionally, QGIS has the Proj program with which you can transform coordinates. The QGIS program is free, but it has some bugs. Proj can also be downloaded from the Internet.

For example, if you take a measurement and get a point in NAD83(2011) (RTK result is in NAD83(2011) if the coordinates of the base reference station are in NAD83(2011)), you can convert its coordinates to NAD83/Arizona Central(ft):
echo “-111.95 34.05” | cs2cs EPSG:6318 EPSG:2223

It seems like a lot of work, but once I do it I’m happy.

Do not transform to WGS84, because these transformations have very low accuracy of around 2m or worse.

Just a simple line between two points with post locations every 12 feet.
I ended up just doing it the old fashioned way and ran a string marking off the distance with a tape measure.

I played around with Google earth and SW maps for a few hours with no luck.

Maybe I’m stupid.

I know the surveyor app field genius can easily do this but it costs thousands and they won’t even sell to private individuals.

The survey industry is trying to keep us out

You read everything correctly, but you’re at the beginning. Unfortunately, this world doesn’t look like the marketing materials describe it. False measurements are a nightmare, i.e. supposedly good measurements, but after repeating them, it turns out they’re not.

If you have time and want to try to set up these posts according to the procedure I described in the first post, all you need are the plot coordinates in NAD83/Arizona Central(ft).

Google Maps uses its own global coordinate system. These are probably maps for tourists, where the location of objects relative to each other is important, not the precise position. For example, you know that your car is parked by your house, but you don’t know how far away it is. It’s also useful for finding stolen or lost items.

Using a string to draw a straight line at a distance of, for example, 100m can be very troublesome, because even a light wind bends the line. It’s worth taking a closer look at this.

If you wanted to mark a straight line with posts, you could:

  1. In the field, make an RTK of the line end points,
  2. Import RTK data (fence end points) to QGIS onto the CRS layer NAD83(2011) EPSG:6318,
  3. Export this layer with the new NAD83/Arisona Central(ft) system selected,
  4. Open the exported layer,
  5. Create a new linear layer with the NAD83/Arisona Central(ft) system and draw a line on it connecting the end points,
  6. Now, in short, draw points (posts) arranged along this line.
  7. Export the layer with the new NAD83(2011) EPSG:6318 coordinate system selected,
  8. Take the coordinates of these points and in the field with RTK place the receiver in the places where the posts are to be.

my home designer pro CAD program will import XYZ coordinates, maybe I can draw it up there and export it as a CSV back to SW maps
there’s a reason functionality like this is missing, its so obvious that people would need it.

I think you’re off on a tangent about NAD etc, we’re just talking about making points along a line between two points, a very simple exercise, yet it’s not available unless you lay out thousands for a survey app.

OK. The question remains open.

In fact, the code required to divide up the interval and calculate your post locations is just a few lines long. Most of the open source GPS libraries contain the functions required for the task.

thanks for the info, I’ll figure it out

You need two functions: “course to” (available in, for example TinyGPS++ and other Arduino libraries) that will give you the bearing and distance between the start and endpoint coordinates and a function that does “bearing shoot”, that is, calculate the GPS coordinates of the next location along that bearing, a given distance from the starting point, available in ArduPilot and other open source navigation libraries.

A useful web reference for these functions is Calculate distance and bearing between two Latitude/Longitude points using haversine formula in JavaScript, (which includes calculators on the page) but if you like I can dig up C code that works.

They won’t be cm-level accuracy but fine for building a fence. :wink:

ok that’s easy cause when you draw a line between two points in SW maps or other it gives you the exact bearing and distance, then can upload to SW maps and use the stake function.

This Python code may help:

If I were building a fence, I would expect cm-level accuracy and mm-accuracy in the calculations. Building a fence is not like flying a drone.

This code doesn’t help, it just gives me a headache.

Perhaps the OP isn’t building the type of fence you have in mind.

Yes, maybe he’s building a fence for his hamster and meter-level accuracy is enough for him.

Big hamster!

it’s just for cows. people build them a few feet inside the property line to avoid problems anyways

Maybe not big but fast running.

you want a barbed wire fence straight cause it will make it stronger when it’s tensioned. if it’s bending back and forth on the posts it’s no good

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I also thought that GPS could be helpful in making such a fence. However, the industry has not thought about such an application so that it is easy for the user.

First you need to determine the position, and then you can think about the gap resulting from the bending wire.

Well, then drive the posts in by eye. Kick the end posts in. Then the other person looks in line through the end posts and you knock in the intermediate posts.