Where the River Begins

Source: Karnali River - Wikimedia

Type: Investigation

Theme: Coding

Grades: 6, 7, 8, 9, 10, 11, 12

Learning Target: Students will use precision while creatively developing a procedure protocol for measuring the length of a river.


This project is for groups of two.

  1. Select a river anywhere on the planet.
  2. Use Google Earth Pro to create a KML file of river using a path (keep your path nodes below 5000). Begin at the mouth/delta of the river.
    (If you choose a very long river or one with many twists and turns, you will need to decide how to simplify your path, otherwise it will take too long to create a path. This is OK. Use logic in the process of simplifying.)
  3. Extract the latitude and longitude data from your KML file. Use Notepad++ to convert data to a data table which can be imported into Desmos (tab-delineated).
    1. High School students will use whatever means they would like.
    2. Middle school students will be provided full scaffolding and structure through Notepad++ the find and replace functions.
  4. Paste tab-delineated data into this Desmos map. https://www.desmos.com/calculator/2xy0orkpwy


  1. PowerPoint or Word document.
  2. Name of river and location.
  3. Desmos graph with river path (with points turned off).
  4. Photos and brief description of the river.
  5. Write a step-by-step procedure or flow chart for measuring river length.
  6. Answers to the following questions.
    1. Where does your river begin?
    2. How did you extract ordered pairs from the KML data?
    3. Research river length and determine calculation error. (Absolute error divided by actual length as a percent.)
    4. Do you feel that your calculation was more correct? Why?
    5. What would have been a more accurate way to measure the river length?
    6. What's your favorite river song?
  7. Peer Reviews, revisions, and references.

Tips for Using Google Earth Pro

  1. Use keyboard arrow keys to move around while you are creating points.

  2. Click on a point to remove. Right-click. Right-click repeatedly to remove multiple points.

  3. To add more points to the end of a path, click on the final point in a path and start adding new points.


Exit Ticket
CCSS Math Practice
  • I can model with mathematics.
  • I can attend to precision.
NGSS Crosscutting Concepts
  • Systems and System Models