Maps

Maps are drawings of the earth's surface. They show where things are located. Maps show visible features such as roads, rivers, lakes, etc. They also show things you cannot see, such as boundaries.

Maps are made up of a few parts, usually they have:

• Compass rose: A figure on a map that shows the directions (north, south, east, west).
• Map legend: A visual description of symbols used on a map and what they mean.
• Scale: Shows how distances on a map are related to actual distances.

Have you ever used a map?

Survey

Land surveyors examine and record the features of an area of land in order to construct a map or plan.

When planning the construction of the the Transcontinental Railroad, ​surveys were needed to find the best route.​

This is one of the surveyor maps used in the construction of the Transcontinental Railroad:

Did you notice the four landforms Judah mentioned?

Theodore Judah said that Surveyors notice:

• water‐courses.
• ravines.
• elevations to be overcome.
• undulation of ground.

Here's what those all mean and what Judah would have done when he ran into them, look at the symbols on each page, you'll use these later:

Water Courses: Rivers, streams, lakes, etc.

Sometimes you have to build bridges over waterways.​

One of the first waterways Judah ran into was the American River, a thirty-mile-long river in California that runs from the Sierra Nevada mountain range to its confluence with the Sacramento river in the Sacramento Valley.

Judah designed this bridge over the American River and it was completed in 1863. ​

Elevations to Overcome​

When you hit a hill or mountain you either have to go around, over, or through it. ​

Trains cannot travel over hills that are too steep, so Theodore Judah chose to cut through a lot of hills or mountains to make it easier for trains to travel.

At bloomer cut in Auburn California, Judah chose to go right through the 1,000-foot-long gravel hill. ​

Granite hills were another obstacle Theodore Judah had to face, and sometimes he chose to go through them too!​​

Your Turn!

Use a piece of paper and draw a map of the route you take to school. Take note of any obstacles you come across. Are they like any of the obstacles a surveyor would encounter?

• Do you live near a river or creek?
• Do you ever cross any roads or freeways?
• Have you noticed any hills near where you live?

These are all things to put on your map! Get creative and design a map that would make Theodore Judah proud!

Here's an example:

Do you see all the parts of a map that you learned about earlier?

If you would rather work on your computer, press this button:

If you live close to your school, you may not notice any bridges or tunnels. Look for these things the next time you take a long drive.

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Think about why you travel over a bridge or through a tunnel and remember that Theodore Judah had to plan a route for the railroad in which trains could travel safely.​