Read layered maps the way GIS does: overlay and find the pattern

Grade 9 Social Studies Worksheet

Circle the best answer.

1. Read this first

   Use this

   Card C. Egypt: water, farms and people, drawn as see-through layers on one base map. Egypt's land area is about 1 million km². Layer 1 (water): the Nile flows north through Egypt to its delta on the Mediterranean Sea. Layer 2 (farmland): cultivated land, about 35,000 km², or about 3.5% of Egypt's land, lies along the Nile and in the delta; the rest is desert. Layer 3 (people): almost all of Egypt's people live in the Nile Valley and Delta, which cover only about 5% of the country. Key: blue = river; green = cultivated land; dark shading = where most people live; tan = desert. Note: nine governorates of Lower Egypt lie in the delta, and ten of Upper Egypt line the Nile from Cairo south to Aswan.

2. 1.

   Jun overlays the farmland layer on the Nile Valley and Delta (about 5% of Egypt's land). About what share of the valley and delta is cultivated?

   • About 70%: the valley and delta cover about 50,000 km², and 35,000 km² of it is cultivated
   • About 3.5%, the share of Egypt's land that is cultivated, since the overlay keeps the same share inside the valley
   • About 5%, because the valley and delta cover 5% of the country and so the farmland fills the same share
   • About 35%, because the 35,000 km² of farmland is taken out of 100,000 km² of valley and delta
3. 2.

   Pia says: "The Nile makes almost all of Egypt's people live along it." What do the layers support?

   • The note is wrong, because just 3.5% of Egypt is farmland and so most people cannot depend on the river
   • Nothing follows, because a map of three layers cannot show anything about where people live
   • The people, farmland and river layers line up along the Nile, but the overlay does not show why people settled there
   • The note is right, since the overlay shows the people layer sitting on top of the river layer, which shows the river caused it
4. 3.

   Bo compares the shares on Card C: the valley and delta are about 5% of the land, and almost all people live there. What follows about crowding?

   • A density of about 20 times the desert's, since 95% divided by 5% gives 19 and 19 is about 20
   • Far more people per square kilometer in the valley and delta than in the desert that makes up the rest
   • Higher density in the delta than in the valley, since the delta is the part nearer the sea
   • About the same density across Egypt, since the cultivated 3.5% and the settled 5% are close in size
5. 4.

   Milo asks what the layers show about the 35,000 km² of farmland and the 50,000 km² of valley and delta. Which statement is right?

   • The uncultivated land is desert, because the key shows tan for desert and nothing else is left over
   • About 15,000 km² of the valley and delta is not cultivated, so settlement and other land share it with farms
   • About 1.5% of Egypt, since 5% less 3.5% is 1.5% and that is the share left over
   • Nothing is left: the cultivated land fills the valley and delta, and so the 5% and 3.5% layers are the same

6. Use this

   Card D (made up for practice). A delta district with 12 villages, checked against two layers. Layer 1 (canals): 9 villages stand within 1 km of a canal. Layer 2 (farmland): 8 villages stand on cultivated land. Overlay result: 6 villages are both within 1 km of a canal and on cultivated land. Key: line = canal; green = cultivated land; square = village. Note: in a GIS query, AND keeps places that meet both conditions, OR keeps places that meet at least one, and NOT removes places that meet a condition.

7. 5.

   Zee runs a query on Card D: villages within 1 km of a canal AND on cultivated land. How many villages does it keep?

   • Nine villages, the ones within 1 km of a canal, since AND takes just the first layer
   • Seventeen villages, the 9 near canals plus the 8 on farmland, counted separately
   • Six villages, the ones that meet both conditions, as the overlay result states
   • Eleven villages, the ones that meet at least one of the two conditions, 9 + 8 - 6
8. 6.

   Ren runs: on cultivated land AND NOT within 1 km of a canal. How many villages does it keep?

   • One village, the one that meets neither condition, since NOT picks out the village left out
   • Two villages: 8 on cultivated land, minus the 6 that are also within 1 km of a canal
   • Three villages, the ones within 1 km of a canal but not on cultivated land, since NOT removes farmland
   • Eight villages, because NOT just removes the villages near a canal that are not farmland
9. 7.

   Esme compares two shares on Card D: villages on farmland that are near a canal, and villages near a canal that are on farmland. Which is right?

   • 75% of farmland villages are near a canal (6 of 8); about 67% of canal villages are on farmland (6 of 9)
   • Both are 6 of 12, which is 50%, since the district has 12 villages and 6 meet both conditions
   • Both are 75%, because the overlap of 6 is the same in each and so the share must be the same
   • About 67% of the farmland villages are near a canal, and 75% of the canal villages are on farmland
10. 8.

    Noah says: "Canals cause farmland, because 6 of the 9 canal villages are on cultivated land." What does Card D support?

    • A link, since 6 of 9 canal villages are on farmland, yet 2 farmland villages have no canal near
    • The claim is right, because most canal villages are on farmland and so the canals made the farmland
    • The claim is wrong, because 3 of the 9 canal villages are not on farmland and so canals do not matter
    • Nothing can be said, because 12 villages are too few for any link between canals and farmland

11. Use this

    Card C. Egypt: water, farms and people, drawn as see-through layers on one base map. Egypt's land area is about 1 million km². Layer 1 (water): the Nile flows north through Egypt to its delta on the Mediterranean Sea. Layer 2 (farmland): cultivated land, about 35,000 km², or about 3.5% of Egypt's land, lies along the Nile and in the delta; the rest is desert. Layer 3 (people): almost all of Egypt's people live in the Nile Valley and Delta, which cover only about 5% of the country. Key: blue = river; green = cultivated land; dark shading = where most people live; tan = desert. Note: nine governorates of Lower Egypt lie in the delta, and ten of Upper Egypt line the Nile from Cairo south to Aswan. Card D (made up for practice). A delta district with 12 villages, checked against two layers. Layer 1 (canals): 9 villages stand within 1 km of a canal. Layer 2 (farmland): 8 villages stand on cultivated land. Overlay result: 6 villages are both within 1 km of a canal and on cultivated land. Key: line = canal; green = cultivated land; square = village. Note: in a GIS query, AND keeps places that meet both conditions, OR keeps places that meet at least one, and NOT removes places that meet a condition.

12. 9.

    Luz says the delta district is a good sample for Egypt's delta. What does Card C say that Card D cannot?

    • Card C shows the delta has more villages than the valley, so Card D should have more villages near the sea
    • Card D is a random sample of Egypt's delta villages, so its 6 of 12 can be used for the whole delta
    • Card C includes the canals in the delta, so it can check Card D's canal layer
    • Card C gives real land areas for the whole country, while Card D is a made-up sample of 12 villages

13. Use this

    Card D (made up for practice). A delta district with 12 villages, checked against two layers. Layer 1 (canals): 9 villages stand within 1 km of a canal. Layer 2 (farmland): 8 villages stand on cultivated land. Overlay result: 6 villages are both within 1 km of a canal and on cultivated land. Key: line = canal; green = cultivated land; square = village. Note: in a GIS query, AND keeps places that meet both conditions, OR keeps places that meet at least one, and NOT removes places that meet a condition.

14. 10.

    Tala asks how many of Card D's 12 villages meet neither condition (near a canal, on cultivated land). What is the count?

    • Zero villages: 9 near a canal plus 8 on farmland is 17, which is more than the 12 villages
    • One village: 12 minus the 11 that are near a canal or on cultivated land
    • Three villages: 12 minus the 9 near a canal, since the rest are not near water and so are left out
    • Six villages: the villages that meet both conditions, since NOT removes them from the district