Participant Forum: Contour Mapping

Picture of Michael Burns
Participant Forum: Contour Mapping
by Michael Burns - Friday, 31 January 2020, 4:55 PM

After you have completed Activity 4.2 share a photograph, map or picture of your work along with a commentary which briefly answers the following questions:

  • What was your experience building the device you chose?
  • Where did you cite your contour line, and why?
  • How did you find mapping contour? Was the line what you thought it would be?
  • How do you see potentially using this technology in the future?

Provide your perspective and encouragement to others.

Discussions provide an opportunity to engage with others who are learning the material. Please take your time crafting your posts. Check for grammar or spelling errors.  When making your first post to the weekly forum start a new discussion topic. You are encouraged to respond to discussions started by classmates. You are required to post at least once in the forum each week.



Picture of Kathy Partridge
Re: Participant Forum: Contour Mapping
by Kathy Partridge - Thursday, 6 February 2020, 9:49 AM

For some reason, there's no "Start a new topic" button on this will only let me reply.

I found the A-frame very easy to build.

This wasn't part of the assignment, but I decided that I wanted to better understand the slope of my front yard for a future addition I have in mind, so I started here. Also, this area is the highest on my property and faces southwest so there was more bare ground, especially under the pines.

(Above) My first task was to figure out my contour intervals and mark them as starting points for my contour lines. I used grade stakes, an 8’ and a 12’ 2 x 4, a level, and a 6”block as a prop for the “free” end of the board. It took some patience, but I was able to find and mark the starting points of 5, 6” contour intervals down the slope of the yard.  Leveling anything is always fussy work, so this step was harder than actually mapping out the contours with the A-frame. Finding the contours though, was kind of addictive. It’s fun to see where the line will go next.

(Above) Also, I did two contour lines as I wanted to see their relationship to one another. The orange (flags) line is 6” lower in elevation than the pink line. The lines “behaved” pretty much as I thought they would. A few flags seemed abruptly out of alignment from what I expected, but I double-checked them and they are correct. I wonder if it’s related to the frost that’s in the top inch or so of soil in some spots.

I'd really like to get out there and finish this using the remaining 3 grade stakes but it looks like the weather will delay things. We got several inches of wet snow overnight (no more bare ground!) with more predicted tomorrow. Eventually, I will transfer these lines to my base map, though I'm still deciding the best way to do that. I’ll be using this technique to map out swales, raised beds and elevation drawings of the addition I’d like to have built. 


Picture of Mike Cooper
Re: Participant Forum: Contour Mapping
by Mike Cooper - Thursday, 6 February 2020, 7:19 PM

What was your experience building the device you chose?

    • I found building the A-frame to be very easy.  We constructed two A-frames from two pieces of scrap pvc found on campus.  Lengths were secured by either twine or screws that we had on hand. No items had to be purchased.  Four people constructed two A-frames in fifteen minutes.

Where and why did you cite your contour line?

    • We ran two contour lines (red lines) initially 10 ft apart from the northwest corner of the garden in hopes of delineating a possible swale site for plantings along its northern edge.  Unfortunately, the contours proved our assumed runoff direction (outlined arrow) to be incorrect (black arrow represents updated direction) making the site less than optimal for a swale.

How easy or hard did you find mapping contour? Was the line where you thought it would be?

    • The process itself was easy, but time consuming.  It took forty minutes for a team of two to mark 200 feet of contour line.  However, it did show that our initial assumption of contour direction was almost 90 degrees off.   

 What potential do you envision for using this technology?

    • Our site’s size is small enough where an A-frame could be used to map the entire area.  It is very easy to use and accurate. Running multiple contour lines could provide relative slope.  Using a protractor, degree markings could be added to the cross piece allowing the user to measure slope.  We will continue to use the A-frames to mark potential swale and drain sites. 

Picture of Kathy Partridge
Re: Participant Forum: Contour Mapping
by Kathy Partridge - Thursday, 6 February 2020, 9:10 PM

I used PVC too. I figured it would be lighter than wood. Fastened the joints with carriage bolts and wingnuts.

Did you use the weighted string? I found that waiting for the weight to stop swinging every time I adjusted the leg a fraction of an inch drove me crazy. I gave up on the string and clamped a 24" level to the cross piece. That sped things up considerably - important since I was racing the weather and needed to finish yesterday before the snow moved in.

Picture of Mike Cooper
Re: Participant Forum: Contour Mapping
by Mike Cooper - Saturday, 8 February 2020, 7:16 AM

Hi Kathy - I did use the weighted string and it did require a lot of time to run the contour.  In the future, I think I will follow your idea and use a level.

Picture of Laura Barry
Re: Participant Forum: Contour Mapping
by Laura Barry - Monday, 10 February 2020, 12:46 PM

great idea with the level! TY

Picture of Elise Zvirzdin
Re: Participant Forum: Contour Mapping
by Elise Zvirzdin - Saturday, 8 February 2020, 6:01 PM

I chose the A-Frame because it was a quick and easy option for my site.  

I used materials that I had on hand:

  • Two tree branches

  • Twine

  • A level for the bracing beam (as per the recommendation from other class members)

  • Mini bungee cords for attaching the level

  • Neon pink flags

It was quick and easy to put together. I assembled it indoors so that the level was on even ground, then I took it outside.

Mapping the contour was the fun part!  The neon flags are a great idea in the winter, because they worked even in the frozen ground.  I imagine they would be great any time of year, because they are easier than pounding stakes in the ground.

I chose this line because it's right in the middle of our yard.  It's a high traffic area, as you can see from all the sledding marks in the snow!

The contour line didn't go where I thought it would.  Elevation can be deceiving when you are outside.  

The level made this project much easier than a weighted string, a tip I got from other students in this class.  I was able to map it out very quickly.

It would be fun to go out and map more lines when I have time this Spring.  It's an interesting thing to see for making pathways or deciding where drainage should go.

(I attached the PDF of my assignment in case anyone wanted to see ALL the pictures)

Picture of Laura Barry
Re: Participant Forum: Contour Mapping
by Laura Barry - Monday, 10 February 2020, 12:45 PM

My husband always has extra wood materials around so my family worked together to build one from leftover trim scraps and my gardening yarn and my lucky horse shoe as the “plumb” or level. We went directly off the video and had no issues in assembly.


We did many contour lines. The one in the picture was from my front yard because that is visually the greatest slope area and we are looking at finding ways to divert the water in the front so it doesn’t enter the side garage. Both my husband and I laughed because we didn’t think the contour line would move the way it did.

 I am so excited to continue to use this in the front and back yard. It was also an excellent tool for my kids because they thought we were crazy moving the a-frame around the yard.  Hopefully I can integrate this into my class in a few weeks as my students are waiting for a grant approval to extend our garden and the area they want to use has a very steep grade.  This will help them determine how to plant and what options are best.

I am struggling a bit in our back yard because we have existing irrigation.  So, we may not use as many swales but instead optimize our water catchment system and hopefully tie into the irrigation.





Picture of David Wheir
Re: Participant Forum: Contour Mapping
by David Wheir - Tuesday, 11 February 2020, 7:46 AM

I agree that lashing a level to some sticks was the quickest solution to building an A frame!  Although I appreciate the stone age simplicity of the hanging weight to find level.  I love this exercise but it's a little frustrating since I don't think I can really take full advantage of this yet.  My garden is on a rooftop - so there's nowhere to sink the water - but finding a level contour line is something I'll definitely use in the future.  I'd like to take my A frame to the park and try to find some contour lines there.

The task wasn't very hard but the results were surprising.  I definitely expected the roof to be more level (wishful thinking) or square but that was not the case.  The most interesting find was that the line I was finally satisfied with ended up following our most used desire line!  I think we innately sought out the level point on this roof when we were laying out furniture and all that.

I'm going to post the pics as an attachment since they both seem to upload sideways.  Apologies - I've tried to reformat this a frame pic but can't get it to stand up right!



Picture of Lucas  Moore
Re: Participant Forum: Contour Mapping
by Lucas Moore - Tuesday, 18 February 2020, 11:06 PM

I found this map of my land and the contours on a government website. I still need to complete the activity in person, but the contour does seem pretty straight-forward. It descends about 200 feet (a pretty steep slope!) going down to the West. I will chose to do the A Frame with a level, as folks have suggested. I know there will be subtle changes in the lines. I want to build some swales in an orchard.