Wednesday, October 9, 2019

SearchResearch Challenge (10/9/19): Why are there contour lines here?

As I was flying to Seattle... 

... I had the window seat that faced east as we flew north.  

Not long after we left SFO, I was staring out the window (because looking out an airplane window when you fly over wilderness is just the best thing you can do), and I saw the most remarkable thing.  

It looked like some giant hand had drawn all of the contour lines on the hills below. 


As you know, contour lines on a topographic map mark a constant elevation.  For instance, here's a sample of a topo map with contour lines at 5400 feet, 5600 feet, etc.  As you can see, there's a steep cliff on the right side of the map, with a more relaxed flat spot on the left.  

Sample topographic map with contour lines.

But the idea of "contour lines" is an artificial way of looking at the land.  They're imaginary lines that are drawn to give the reader an idea about what's going on with landform.  

So you can imagine my surprise when I looked out my window and saw this, with what looks like contour lines in reality...  

Alas, I didn't have my camera handy.  This is an image from Google Maps of the place I
saw out the window.  It really does look like this!

When I got home to my laptop, I searched along the flight path and found the location.  (See above.)  

Interestingly, if you look at the Terrain view of this location, you'll see something remarkable: 

If you put these side-by-side, they're amazingly similar. 

The "contour lines" in the satellite photo are clearly lines of trees or bushes or something growing.  This amazes me.  I thought contour lines were an artificial construct, a visualization device mapmakers would draw on a map to give a sense of shape on an otherwise 2D image.  

But how is this possible?  Did some maniac cartographer go out there and plant bushes along the contour lines?  

This leads to our SearchResearch Challenge for the week: 

1.  What is going on with those naturally green "contour lines" that seem to show up naturally?  Why are they growing along the lines of constant elevation?  What is going on?

Any ideas?  

In truth, I have no idea what's going on here, and what's more, I don't have a great idea about how to find out!  We'll figure this one out together.  

One useful piece of information:  The center of this map is at 40.081801, -121.903088 (link to Google Maps at this location)  

When you figure it out, let us know the answer... AND tell us how you did it.  We learn from each other, so also be sure to tell us the paths you pursued that didn't work out.  

Search on!  


  1. I also don't have idea. My first thought was maybe there is something like bamboo that grows to same height and covers big areas in short time.

    Then visited Google Maps and read Tehama California. Searched for it and Wikipedia says it is the first area that suffers flood and that is homes need special construction. I wonder if natural erosion could be the answer

  2. Visited Google Maps again on a bigger screen and noticed "Ishi Wilderness" therefore, SRS for that and

    Wikipedia says: "The land is a series of east-west running ridges framed by rugged river canyons, with the highest ridges attaining elevations of 4,000 feet (1,200 m)."

    In the external links, comes: "The Nature Explorers Ishiland Expedition" but link is broken. Therefore searched for that.

    And found the Playlist on YouTube Videos looks very interesting. Total run time >50 minutes

    [Ishi wilderness unknown facts] and later [ Ishi wilderness photos

    Sundown in Ishi Wilderness

    Ishi Wilderness Journal on FB

    [Ishi wilderness topographic map|view] not yet finding some new clue

  3. I like the new look. I never knew there was a Terrain option in maps til now. THe blog is all squished into a narrow vertical band, near unreadable. Hmmmm. In Reader view there is no place to comment. Bugs, darn bugs. Jon TU

  4. I zoomed out the Google map looking for the name of the area and noted the Lassen National Forest. Searched for ["Lassen national forest" topography] and got to Wikipedia. The Wikipedia page for Lassen National Forest links to a page on the Ishi Wilderness which has a section on flora and fauna, describing which plants grow on the slopes and why. I love looking out of plane windows! On holiday to the US last year, we were fascinated by little square things on the ground over Texas. Turned out they were old oil wells, a sight we don't have in NZ.

  5. Looked at the map and found the site label Ishi Wilderness. Did a Google search using terms ishi wildneress and geomorphology and ishi wilderness and topography.
    Google Books returned the Directory of the Geologic Division, U.S. Geological Survey: With Staff and identified Jocelyn A Peterson as an expert in the area. I add her to my search terms and came up with U.S. Geological Survey Professional Paper, Issue 1300, Part 1- which indicated that the area had been covered in a 200 ft volcanic mud flow in the late Pliocene. My first guess is that the landscape is formed from water erosion of the mud flows and what you are looking at a river terrace gravels that relate to water levels at different points of time since then. Will come back and look at this in more depth later.

  6. "Glacial landforms such as moraines and outwash deposits “overprint” much of the volcanic foundation. The alteration of volcanic rocks by hydrothermal processes facilitated glacial erosion, and glacially eroded features such as U-shaped valleys, cirques, and arêtes occur throughout the park."
    Lassen volcanic center
    new terms… to me…
    "Glaciers also polished and scratched striations and grooves on bedrock surfaces, and formed cirques and arêtes at high elevations, and roches moutonnées in valleys."
    " …tephra (deposits of volcanic material ejected from a volcano)."

    Lassen pdf
    1914 to 1917
    a view… appears to be just north of where you were looking…

    1. New words for me too, Remmij.

      Searched [Lassen volcanic unknown facts]

      New things:
      Luis Arguello, Spanish officer first European to sight peak: 1821. Source Easy Science for kids. The 4 kinds of volcano are here ( those types include shield, plug dome, cinder cone, and composite) snow algae can be seen here too.

      Soft school site also gives interesting facts

    2. We all love Hawaii, volcanoes and #ThejoyofSearch that is why I share with you this video : enjoy

  7. Replies
    1. What you're seeing are mostly property boundaries. Some ranches have horses and cattle, that pretty much eat everything inside the fence boundaries. That's mostly what you see.

      The "curious patterns" you see are mostly clear cuts (or near-clear cuts) from forestry that goes on in the private lands around Highway 32 in the SE corner of the Lassen National Forest.

  8. thanks Dan, am still seeing some things that don't seem right…
    see imgur images below - included geo-coorindinates if you want to look on Maps
    along with a map link - the way things are rendering just seems off - kinda like a masking exercise - sometimes used in Maps?
    the clear cut detail zoom is particularly odd to my eye… the zoomed-out
    image of that area looks like a wrinkled table cloth (thought that was a good
    contrast to ikijibiki's comment about drill sites/well-pads in Texas)
    the Tehama County image seems to be the same "landscape square" pasted
    over & over and the "green patch" is a full mystery…? like an overlay? curious as to what you see?
    imgur - is it just my imagination? - unedited, grabs directly from Maps - do they render the same for you?
    Tehama county on Maps - striations almost look like corduroy…

    1. These are either stitching artifacts (e.g., when the source images are merged--"stitched"--together, you might get things like this. But when I go to these locations, I don't see what you see.

      When I look at the controller (lower right) of your image, it looks like you're using another version of the application. Can you tell us what your browser is and the version number? (e.g., is this Safari?)

    2. Hi Remmij
      Your second link in this post (Google Maps) my imagination shows the figure of Ghostbusters's Marshmallow. Someone else see the same?

    3. Hi Dr. Russell, Remmij and everyone.
      About the marshmallow: Here is what I saw when clicked your link Great imagination or marshmallow? How knows!

      Then searched ["Contour lines" Google Maps] and similar without Google Maps

      What Do Contour Lines on a Topographic Map Show?

      Also reading noticed the term "quad 7.5 maps." What is that? I searched. Wikipedia says: "A "quadrangle" is a United States Geological Survey (USGS) 7.5-minute map, which are usually named after a local physiographic feature. "
      USGS says:

      Yet didn't know what 7.5 minute meant so added meaning to my previous query: [7.5 quad map meaning]
      The answer includes latitude and longitude coordinate system

      Read an article in Stack Exchange but didn't notice how I got to it. Therefore [7.5 quad map meaning stack exchange] still can't find that article but read other stuff adding "Stack Exchange" and the only result is also very interesting and sends to good articles.

      [Lassen volcanic Stack Exchange]

      Butterfly Migration over Lassen Peak And visited the California tortoiseshell


      What are these mysterious craters?

      And today, read
      How mapmakers help indigenous people defend their lands

    4. Dan, see how lucky you were to be safely in a plane?

      …do you wear a tie while you fly?… a different time…
      the plane window
      @ 20,000 feet…

      Mt. Lassen… could be Area 51.6249929… from Reptilius… ;•P

      baseball size rock
      nice photo of Lassen above - the SERP
      SERP supplemental - before & after
      the truth is out there… just not here…
      "CALIFORNIA, MT. LASSEN - Two young men reported the discovery of a glazed tunnel behind an outcropping of rock at about the 7500 ft. level on the slopes of Mt. Lassen. They explored the cavern using a strange tunnel
      vehicle and were captured by men dressed as surface people who were known as the "horlocks", humans under the total mind-control of some alien force, only to be rescued by an underground resistance force. Others have
      reported abductions near Lassen by a human - reptilian collaboration. source: AMAZING STORIES magazine, Dec. 1946; Mt. Lassen Natl. Park"

      …Joe? thought his name was Dick… married to a woman named Jane…
      "The Mt. Lassen Entrance Mt. Lassen in Tehama County, California is an entrance to a large underground city. Near the foot of Mt. Lassen is a town called Manten. A man named "Ralph B. Fields" lived (lives?) there, and found the entrance to the underground city. His friend "Joe" was with him. The cave entrance is in the side of the mountain, at a little over 7,000 feet above sea level, and is near a rock outcropping suitable for camping under. "

  9. Anne and Deb here. Of course I knew that Anne would know this area. She actually DROVE through this area this summer on a trip back to California! We started this search by putting in the coordinates in google maps and then zooming out to get a better idea of where this was. Anne knew this was near Lassen Volcanic National Park. Our first thought was this had to do with volcanic flows and that possibly the green was growing in areas that weren't affected by volcanic flow. We found some information on the Ishi Wilderness on this site The description of this area seems to describe what is going on in this area."This is a land incised by wind and water, dotted with basaltic outcroppings, caves, and bizarre pillar lava formations. This is up and down country, a series of east-west running ridges framed by rugged river canyons." We think the green is in these river canyons. We will continue to work on this when we can get a little more time.